Engaging students: Exponential Growth and Decay

In my capstone class for future secondary math teachers, I ask my students to come up with ideas for engaging their students with different topics in the secondary mathematics curriculum. In other words, the point of the assignment was not to devise a full-blown lesson plan on this topic. Instead, I asked my students to think about three different ways of getting their students interested in the topic in the first place.

I plan to share some of the best of these ideas on this blog (after asking my students’ permission, of course).

This student submission comes from my former student Chais Price. His topic, from Precalculus: exponential growth and decay.

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How does this topic extend what your students should have learned in previous courses?

Every year in elementary through high school it seemed like I had some form of standardized test. These test typically consist of various problems, which include patterns and sequences of patters style of problems. I always found it more helpful when being introduced to more complex and intimidating concepts, to relate the general idea to something much more simplistic. When teaching a lesson on exponential growth and/or decay I plan on starting off the lesson with problems like:

exponential1 exponential2

These two patterns are pretty basic and finding the next one in the sequence shouldn’t be to difficult. This begs the question what if I wanted to find some enormous value for n. For questions d, a student can answer the question by drawing or counting but it will take some time. Or the student could find an equation that models the sequence of patterns. The equation would obviously be an exponential. From this point the teacher could discuss how these functions appear on the graph by simply observing what is happening in the sequence. In the first picture alone with the triangles, we only have 4 triangles shown and the first triangle is solid black. If we continue on, the next one in the sequence would represent basically our x values on a graph and the amount of triangles growing exponentially represents the y values. By using this previous knowledge the teacher was capable of relating a new concept with a much simpler approach.

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How could you as a teacher create an activity or project that involves your topic?

Has anyone ever asked you if you would rather have a million dollars, or a penny that doubles everyday for an entire month? I heard this question probably when I was in high school. I am pretty sure that I picked a penny that doubled everyday for a month only because it was the least obvious and it seemed like a trick question. However this is an example of how only 31 days explode into a fortune. After the first week of doubling you only have a little over a dollar. In fact you really don’t start making any real money until about the middle of the 3rd week if you chose to have a penny double everyday for a month. It turns out that by the last day of the month you end up with over 21 million dollars. This is once again because the function is growing exponentially. The link at the bottom of the page has a story that uses this same idea about a raja from India who made a young girls request to have a grain of rice double everyday for a month. This story can be fun to read and engaging for the students as well. After the story is read, there is a calendar where the students will fill in each day the amount of rice given to Rani, the young girl in the story. This calendar has a few random days filled in so the students know if they are on the right track. This activity serves as an engage/ explore for more of an introduction to exponential growth. The students could graph this function of type some points into the calculator to see the function explode. Let x represent days and y represent the grain of rice each day.

 

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How can technology be used to effectively engage students with this topic?

Dan Myers is a teacher who developed a style of teaching called the 3 act lessons, which incorporates multiple technology applications such as video recording, as well as imaging and photo editing. Each act is designed to teach a lesson like a movie divided up into parts. I came across this lesson of his which I think is awesome. In act 1, there is a 24 second video with these words at the beginning: “ a smaller domino can topple a domino that is up to 1.5 times larger in every dimension. “ The guy on the video explains that the smallest domino is 5 mm high and 1mm thick. This is all you are given. Then the teacher asks something to the class along the lines of “ If you wanted to topple over a domino the size of a sky scraper, how many dominoes would you need? “ This opens the door for students to both question and reason. Make a prediction and write it down. Have the students write down an answer they know is too high and one they know is too low. That is the end of act one. As we get into act to we need more information just like in a movie. Act 2 answers the question how many dominoes are present in the video. It also provides a data sheet that has the heights f several sky scrappers. This is a very discussion style lesson so in act 2 we would continue to promote discussion and questions. Then finally in act three we come to the conclusion. The man in the video had 13 dominoes and the biggest one was barely up to his waste. It turns out that if we were to keep adding dominoes that grew 1.5 times more than the previous one, the 29th domino would be as tall as the Empire State Building. That is exponential growth at its finest.

 

 

Engaging students: Parabolas

In my capstone class for future secondary math teachers, I ask my students to come up with ideas for engaging their students with different topics in the secondary mathematics curriculum. In other words, the point of the assignment was not to devise a full-blown lesson plan on this topic. Instead, I asked my students to think about three different ways of getting their students interested in the topic in the first place.

I plan to share some of the best of these ideas on this blog (after asking my students’ permission, of course).

This student submission comes from my former student Banner Tuerck. His topic, from Precalculus: finding the equation of a parabola from the focus and directrix.

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An interesting way to present the mathematics behind parabolas and their focus points is through the applications it has in science present in our everyday lives. http://spacemath.gsfc.nasa.gov/IRAD/IRAD-4.pdf

The above link includes a great engagement activity for students to do as a group activity. The first exercise presented involves the students in the design of a parabolic dish after observing the properties of a satellite dish with a radio receiver (located at the focus). Once the students have completed the design of the parabolic dish the instructor could then use the second half of the pdf from the link as an elaboration activity. The instructor could either keep the students in the groups or have them work the problems individually. Nevertheless, the second activity would be for the students to work problems one and two, which deal with aiding a bird watcher and a hobbiest in determining the focus points in order to design their parabolically shaped tools. The last problems are excellent real world examples of why one would need to know and apply the mathematics for parabolas. This will encourage students to view everyday objects with a more mathematical respect.

 

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The understanding of the relationship between the focus point and the directrix of a standard parabola is fundamental when students extend their mathematical and science education in post-secondary courses. For example, when students reach multivariable calculus they will graph and study the properties of conic sections on a three dimensional scale. With respect to this topic the students can apply their preexisting knowledge of two-dimensional parabolas to the paraboloids presented in this course. Furthermore, if students from a pre-calculus high school course were to not keep with the theoretical study of mathematics they could benefit greatly from this topic in careers such as architecture, art, or graphic design.

 

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As an instructor of a pre-calculus course one has many technological resources to use in order to construct an elaborate lesson on the directrix and focus of a parabola. For example, modern graphing calculators allow instructors to link their calculator to a projector and show the entire class various parabolas in order to further visualize the changing distances to these specific points. Furthermore, I believe a unique homework assignment would be for students to graph given quadratic equations with an online resource such as http://www.wolframalpha.com/. This assignment would also be a great review of how to apply the distance formula. I recommend having the students check that the points on the parabola are equidistant apart from the focus and the directrix they have already found after graphing and computing. Another idea is requesting (for full credit of the assignment) the students use the following link: https://www.khanacademy.org/math/algebra2/conics_precalc/parabolas_precalc/v/parabola-focus-and-directrix-1

to facilitate their understanding of the definition of a parabola as well as the importance of the focus point and directrix line. This is a way to involve technology while simultaneously ensuring that students review key aspects of the lesson after it was given by the instructor during class time.

References

http://spacemath.gsfc.nasa.gov/IRAD/IRAD-4.pdf

http://www.wolframalpha.com/.

https://www.khanacademy.org/math/algebra2/conics_precalc/parabolas_precalc/v/parabola-focus-and-directrix-1

 

 

 

Engaging students: Compound interest

In my capstone class for future secondary math teachers, I ask my students to come up with ideas for engaging their students with different topics in the secondary mathematics curriculum. In other words, the point of the assignment was not to devise a full-blown lesson plan on this topic. Instead, I asked my students to think about three different ways of getting their students interested in the topic in the first place.

I plan to share some of the best of these ideas on this blog (after asking my students’ permission, of course).

This student submission comes from my former student Andy Nabors. His topic, from Precalculus: compound interest.

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What interesting (i.e., uncontrived) word problems using this topic can your students do now?

I would give the students a problem to find out where they should invest their money. They would be given several options with pros and cons and need to choose the best option for them and explain their reasoning. The problem would go something like this:

You are looking to put your graduation money, a total of $2,498, into a savings account. You have gone to several banks and found the interest rates and start-up fees for making an account there. Which bank is offering you the best deal? Which would you choose and why?

Bank Interest Rate Compounded Start-Up Fee
Bank of America 2.5% daily $65
CitiBank 5% monthly $100
Comerica 3% weekly $50
JP Morgan 1.7% continuously $50
Wells Fargo 3.3% bi-annually $0

 

This material is Pre-Cal, so I assume the students are either juniors or seniors, so they may be looking at having to open a bank account of their own in their near future. Then this would be a relevant question for them to look into and figure out what exactly gives them the best option.

 

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How could you as a teacher create an activity or project that involves your topic?

This activity would be similar to one we did in 4050. At the time of this activity, they would not know the formula for compound interest. I would put the students in pairs and pose the question “Suppose you have $1000 that earns 8% interest. How much would you have at the end of 2 years if the interest was compounded: a.)annually b.) biannually c.)quarterly d.)daily”. Then the students would work in pairs to figure out the answers and I would instruct the students to find a pattern as they worked to make it easier. The students would eventually discover the formula for compound interest compounded for any number. They would then be asked how many times the money would have to be compounded to put out the highest total. The students would discover that the higher number, the more total, but as the compounded numbers increased, the difference between the outputs would decrease. So we could then say that there is a limit to how much the output could be, and that limit would be compounded infinitely. Then we could take the limit and find out what the formula is for finding compound interest compounded continuously.

 

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How can technology be used to effectively engage students with this topic?

Students need to know how to do their own research in their future for things like buying a house or car, choosing whether or not to rent or buy, or other things where they are having to find the best deal and fit for them. This activity would have students researching different banks. They would be asked to find out the details on certain banks’ interest rates. They would need to find out about fees and how many times the interest is compounded. They would need information about at least three banks, and then would need to research on independent sites which bank would be the best to start an account with from the banks they chose. Then they would choose a bank for them based on their own findings and calculations, and would choose a bank based on what an online article said. This would let students form their own opinions based on data they found, and weigh that data against the opinions of others. Their findings and opinions may not match up, and that’s why this activity would benefit them. It’s important that students learn to not take the opinions of others as fact, but do their own research to find the best deal.

 

Square any number up to 1000 without a calculator

The Mathematical Association of America has an excellent series of 10-minute lectures on various topics in mathematics that are nevertheless accessible to the general public, including gifted elementary school students.  From the YouTube description:

Mathemagician Art Benjamin [professor of mathematics at Harvey Mudd College] demonstrates and explains the mathematics underlying a mental arithmetic technique for quickly squaring numbers.

Engaging students: Using Straightedge and Compass to Find the Incenter of a Triangle

In my capstone class for future secondary math teachers, I ask my students to come up with ideas for engaging their students with different topics in the secondary mathematics curriculum. In other words, the point of the assignment was not to devise a full-blown lesson plan on this topic. Instead, I asked my students to think about three different ways of getting their students interested in the topic in the first place.

I plan to share some of the best of these ideas on this blog (after asking my students’ permission, of course).

This student submission comes from my former student Nada Al-Ghussain. Her topic, from Geometry: using a straightedge and compass to find the incenter of a triangle.

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What interesting things can you say about the people who contributed to the discovery and/or the development of this topic?

Sitting down one day pondering, Greco-Roman mathematician Euclid had a light-bulb moment and Eureka, the Elements was created! Right? Well not quite. Back in the day, 440B.C to be exact, a merchant named Hippocrates of Chios, chased after pirates to Athens to recover his stolen property. Unsuccessful, he attended math lectures and compiled the first known work of elements in geometry. Later on, around 350 B.C in the Academy, mathematician Theudius’s textbook was used by non- other than Aristotle. Then came our man Euclid in 300 BC and presented to us the pivotal textbooks, the Elements, which was used in universities until the 20th century. Euclid had compiled previous mathematical work into his Elements although he alone contrived the design and construction of different parts. Euclid’s Elements consisted of 13 books that covered Euclidean geometry, elementary number theory, and etc. For example, in book 4 (IV) Proposition 4, Euclid gives directions to inscribe a circle in a given triangle using a straightedge and compass.

 

http://www.britannica.com/EBchecked/topic/194880/Euclid

http://aleph0.clarku.edu/~djoyce/java/elements/bookIV/propIV4.html

 

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How could you as a teacher create an activity or project that involves your topic?

 

I would set up a Founding Geometry explore activity before telling students anything over Euclidean geometry. In this activity I would want individual work but allow students to discuss in groups. Each person would get an equilateral triangle image, a compass, and a straightedge, not a ruler! First I would instruct the students to find the incenter, middle point of the triangle using only those two tools. This would get the students to think and go through trial and error as they work individually and together. Next I would ask them to write down their steps and discuss with each other. Then I would open class discussion asking the students the steps they took to get the incenter. I would ask thee students if they see anything else with all the lines they drew. Hoping they would describe the angle bisectors. Then I would ask the class if all triangle incenter’s could be found the same way. I would give each student a different shaped and sized triangle and give them time to discover the answer on their own. Once students finished, I would discuss the class the key steps and definitions learned. I would then tell me that they all are founders of Geometry, and tell them about Euclid’s role in geometry. This activity could be easily changed to any parts like how to construct a triangle or even to help prove and understand the Pythagorean theorem.

 

 

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How can technology be used to effectively engage students with this topic?

 

When constructing geometry, trial and error tends to occur. Whether it is an instructor or a student. Graphical Ruler and Compass Editor, GRACE is a great site that allows the user to construct using only a straightedge and compass. By simply producing points and picking from Line, Line Segment, Ray, Circle, Perpendicular Bisector, and Intersection. This could be given to students as they work in class or at home as to not waste paper. It has special features that allow you to zoom in and out doing multiple constructions on one page. It also allows you to create and test axioms. This is tool is great for middle school all the way to university level students. It’s a quick visual that can be manipulated easily. From experience, many times when constructing certain propositions from Euclid’s Elements, I tended to waste time erasing so much and making perfect circles. Plus hand drawings can be tedious for some students. This is easier to use and engage all students including some special education students.

 

http://www.cs.rice.edu/~jwarren/grace/

 

Engaging students: Introducing the terms parallelogram, rhombus, trapezoid, and kite

In my capstone class for future secondary math teachers, I ask my students to come up with ideas for engaging their students with different topics in the secondary mathematics curriculum. In other words, the point of the assignment was not to devise a full-blown lesson plan on this topic. Instead, I asked my students to think about three different ways of getting their students interested in the topic in the first place.

I plan to share some of the best of these ideas on this blog (after asking my students’ permission, of course).

This student submission comes from my former student Kristin Ambrose. Her topic, from Geometry: introducing the terms parallelogram, rhombus, trapezoid, and kite.

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How could you as a teacher create an activity or project that involves your topic?

 

An activity I could do with my students is to have my students sort the different shapes into their own categories. Without letting them know the terms for these shapes, I could give my students several cut-outs of different parallelograms, rhombi, trapezoids, and kites, and have them sort these into four categories. Then the students could discuss how they grouped the shapes, and with the teachers guidance the students would come up with a list of the key characteristics each group of shapes had. Only at the end would the teacher reveal the official terms (parallelogram, rhombus, trapezoid, and kite) for these categories, and by this point the students would already know the characteristics for each shape since they previously listed the characteristics before they knew the official terms. I believe this would make the process of learning about these shapes more meaningful and interesting since the students would have discovered the characteristics of these shapes on their own.

 

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How has this topic appeared in high culture (art, classical music, theatre, etc.)?

 

Geometry often appears in art, and therefore shapes like parallelograms, rhombi, trapezoids and kites can be found in pieces of artwork. I was able to find a website (http://fineartamerica.com/art/all/geometric/all) where they sell geometric artwork. On this site I was able to find a few pieces that contained parallelograms, rhombi, trapezoids, and kites. Here are a few pictures of artwork that contains these geometric shapes:

horsehat

These shapes can also be found in other forms of art like jewelry, like this trapezoid necklace and kite earrings:

necklaceearrings

Students may find it interesting to see how geometric shapes can be used in different forms of art, and it may even inspire them to create their own forms of geometric artwork or crafts.

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How can technology be used to effectively engage students with this topic?

 

On YouTube, the channel Vi Hart has a video where they create geometric shaped cookies. Here is the link to the video:

During the first two minutes of the video they create √2 rhombus cookies. Then they are able to create other cookie shapes using the rhombi cookie dough. It’s interesting to see the different ways they cook with the geometric shapes, and it could even inspire my students to create their own geometric-shaped cookies. After viewing the video, I could discuss with my students what characteristics they noticed about the rhombus-shaped cookies and this could open up a discussion about what the definition of a rhombus is. After discussing rhombi, we could move on to discussing other kinds of geometric shapes like parallelograms, trapezoids, and kites. We could also discuss the similarities between these kinds of shapes, and how they connect to each other.

 

References:

 

Geometric Artwork:
http://fineartamerica.com/art/all/geometric/all

 

Vi Hart Video:

https://www.youtube.com/watch?v=_n1126GoxbU&list=UUOGeU-1Fig3rrDjhm9Zs_wg

 

Fractal Geometric Dog, artist: Budi Satria Kwan

http://fineartamerica.com/featured/fractal-geometric-dog-budi-satria-kwan.html

 

Red Parallelogram art:
http://www.wetcanvas.com/forums/showthread.php?t=601147

 

Trapezoid necklace:
https://www.etsy.com/listing/53449025/brass-trapezoid-necklace

 

Kite earrings:
https://www.etsy.com/listing/168803451/modern-geometric-earrings-of-angles-and?ref=market

 

 

 

 

Engaging students: Translation, rotation, and reflection of figures

In my capstone class for future secondary math teachers, I ask my students to come up with ideas for engaging their students with different topics in the secondary mathematics curriculum. In other words, the point of the assignment was not to devise a full-blown lesson plan on this topic. Instead, I asked my students to think about three different ways of getting their students interested in the topic in the first place.

I plan to share some of the best of these ideas on this blog (after asking my students’ permission, of course).

This student submission comes from my former student Kelley Nguyen. Her topic, from Geometry: translation, rotation, and reflection of figures.

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How could you as a teacher create an activity or project that involves your topic?
With this topic, I would definitely do an art activity, where students will construct tessellations of their choice. I would ask the students to print out a picture of their favorite animal, sport, pattern, etc. In class the following day, we would begin our drawings and the students will take the assignment home and finish it as a project. I would start them off in the top left corner, making a reflection of the original image. Then, we’ll turn the image 90 degrees, making a rotation of the original image. We’ll repeat this process until the entire page is complete. In this case, using an 8.5” x 11” sheet of computer paper may be the best choice so not too much time is spent on the art of the subject rather than the concepts behind it. If teachers wanted to make it an extra credit assignment, using a poster board can be a good idea and can be hung outside the classroom.

reflection

Once the students are complete with the project, we will all reflect on what they see. They’ll be able to point out the turns and flips of the tessellation, which will lead us into the topic of transformations.

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How has this topic appeared in high culture (art, classical music, theatre, etc.)?
Translations, rotations, and reflections all appear in the art of dance. Being a dancer involves a lot of movement, including turns, flips, slides, etc. These types of movements are all connected to geometry.
If a dancer spends an eight-count sliding from one space to another, this form of movement is considered a translation in mathematics. For example, in the picture below, the black character slides into the position of the red character. That is a form of translation with movement in dance.

dancer

Mathematically, a translation will look like the image below, where the black triangle translates one unit down and five units to the right.

translate

Now, if a dancer decides to throw a handstand into their routine, this is a form of reflection on the original position.

dancer2Mathematically, a rotation is done by a particular degree. The example below displays an object being rotated 180 degrees about the origin.

rotate

Lastly, let’s say two dancers perform a duet for an upcoming show. Most of their routine contains the same exact movements but in some point of their dance, both dancers reflect each other moves against each other. This form of movement is considered a reflection. For example, in the picture below, both dancers are reflected each other’s leaps away from each other, making a symmetric line down the middle.

dancer3

Mathematically, a reflection is a flipped image across the axis of symmetry. In the example below, the black figure is reflected across x = 3 to create the blue figure.

reflectThe examples provided are just some ways translations, rotations, and reflections are used in art of dance. Most people won’t pick up on the idea of mathematics being used when creating routines, but it’s definitely connected in many ways, movement being one.

green lineHow have different cultures throughout time used this topic in their society?
Transformations can be seen all over the world on streets, in museums, at parks, and downtown as works of art, architecture, crafts, and quilting.

Many transformational designs are found in rugs, quilts, buildings, and pottery from numerous different cultures. These designs gave note to where and to whom these unique pieces belongs to.
Most can agree that the use of transformations is important to art. These geometric designs showed a culture’s appeal of art and architecture. For example, historical buildings are well constructed and decorated to display religious beliefs or honor someone important in the community. These buildings often contain geometric shapes and patterns as an appeal to the population. Specifically, the Alhambra Palace in Spain portrays beautiful tessellation designs throughout its windows and ceilings. The designs are symbols of dynasty and wealth in their society.
Crafts and pottery also play a big role in the importance of transformations within cultures. When studying this form of art, researchers can identify which cultures interacted with other cultures. Each culture alone had their own unique designs that identify them as a whole, which portrayed their way of living and track the journey they took.
Lastly, thinking more modern, we could find that the United States Capitol building located in Washington, D.C. was built on the basis of symmetry. If you’ve ever been inside, you’ll notice that the building contains a lot of interior art work, including tessellations and symbols representing important historical people and events.
References

 

 

Engaging students: Deriving the distance formula

In my capstone class for future secondary math teachers, I ask my students to come up with ideas for engaging their students with different topics in the secondary mathematics curriculum. In other words, the point of the assignment was not to devise a full-blown lesson plan on this topic. Instead, I asked my students to think about three different ways of getting their students interested in the topic in the first place.

I plan to share some of the best of these ideas on this blog (after asking my students’ permission, of course).

This student submission comes from my former student Donna House. Her topic, from Geometry: deriving the distance formula.

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What interesting word problems using this topic can your students do now?

Start with a story:

Two guys (Cyniscus and Protogenes, but they usually went by their nicknames, Cy and Skippy) were hanging out on a Saturday afternoon in ancient Greece. Cy wanted to go to McDolops and get a Filet-O-Squid, but Skippy wanted to go to Athens Fried Pheasant. While they were discussing this, their buddy, Pythagoras, walked by.

Cy:                  Hey, P-Thag! What up? (This is from the original Greek.)

Pythagoras:     Dude! Just gonna grab a bite somewhere. What up with y’all? (Greece is                                        in the south.)

Cy and Skippy told P-Thag about trying to decide where to go. Pythagoras did not want to go to either place — McDolops or Athens Fried Pheasant — because he was a vegetarian. (Pythagoras was also morally opposed to beans. No one knows exactly why. Some say it was because he believed eating beans was akin to eating people. Others think it was because — well, you know what eating beans does.)

So, Pythagoras suggested they go to What-a-carrot and, since they served pomegranates and pancakes, Cy and Skippy thought that was a great idea. But how would they get there?

Cy wanted to walk east down Aesop Avenue to the agora, turn left, and walk to What-a-carrot.

Skippy wanted to walk north up Draco Drive to the temple, turn right, and walk to What-a-carrot.

Pythagoras had more common-sense (or was just lazy) and wanted to find a shorter route. So, he came up with a useful theorem on the spot! (Really – that is just how it happened.) P-Thag wanted to walk straight to What-a-carrot. (Euclid wrote an axiom for this: “Given two points there is one straight line that joins them.” Euclid’s axiom didn’t help on this day – Euclid lived about 300 years later!)

distance1

If Aesop Avenue is 4 stadia long and Draco Drive is 3 stadia long, how far would they walk using Cy’s route? How far would they walk using Skippy’s route? How far would they walk using P-Thag’s route?

What formula did you get? d(distance) = ?

Now, armed with this knowledge, solve the following real-world problem. [I found the following problem at http://www.hamuniverse.com/guywirelengthformula.html ]

It is late and you are sitting at your desk and in the middle of planning your new tower project or antenna support [you are a ham-radio operator] and you’re getting all of the materials, parts, accessories list, etc. together so you can dig deep into your bank account for the needed money to purchase all of the needed supplies.

In your excitement you realize you just can’t wait to get that antenna support mast or that tower you just acquired high in the air so your signal will travel the earth and beyond.

In your planning stage you have looked over your proposed tower or mast site and found the ideal place in which to “plant” it in the ground and you know how high it will be when it is installed.

Now you ask yourself where to put the guy wires for it on the ground…you walk around the area and pick some good locations for each of them hopefully conforming to recommended safe installation procedures. In your observations, you realize that each guy wire will have to be a different length due to obstructions and Murphy’s Law getting in the way. It never fails, Murphy is always looking over our shoulders and picking on us as ham radio operators!

Ok now, stand back Murphy…each guy wire has to go in a specific location whether “Murphy” likes it or not and you know how high the tower or support mast, pole, etc. is so then it hits you… and you ask yourself….how long will the guys [wires] have to be for the locations I have picked out? I don’t want to have to buy more guy wire than I need. After all, my wife says I am cheap!

You look at the tower, pole, mast etc. and your location for the guy wire at ground level and say….well the mast is 50 feet tall, so the length at the location of my first guy has to be at least as long as the mast is high but a bit longer…but how much longer will it have to be due to the angle of the guy coming off of the tower if it is 70 feet away? See the example drawing below for our proposed setup and to get the answer to our question in our fictitious installation.

distance2
In our example above, the tower is 50 feet from the base to the top guy
attachment point and the distance to the first guy is 70 feet…how long is the guy wire!

 

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How could you as a teacher create an activity or project that involves your topic?

Math can become boring and tedious for some students (shocking! – I know.) An activity that will help them learn while having fun will help them remember the lesson. One such activity is useful in learning the distance formula.

If your classroom is not large enough, arrange to have your lesson outdoors or in the gym (at least this portion of the lesson.) Divide the students into two teams and have each team line up in an “L” shape. For example, if you have 10 students on a team, have six or seven line up in a straight line and the remaining students form a line at a right angle to the end of the first line. The number of students in each line is not important as long as the lines form a right angle and each team is lined up the same way.

Give the two students at one end of each team a ball and tell them to pass the ball from one student to the next until the ball reaches the end of the line. The goal is to pass the ball from one side of the team to the other. The team who passes the ball fastest wins the match.

Repeat this game until someone figures out to throw the ball from one end of the line to the other. (You may need to say, “Think about how you can get the ball to the other end faster.”) This will complete your right triangle!

Now you can have a discussion about how going from one end to the other directly is faster than having to go around the corner. (The shortest distance between two points . . .) Someone will probably mention the Pythagorean Theorem and that will give you the perfect opportunity to guide them through the derivation of the distance formula!

 

 

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Begin by asking, “How can not knowing math cost you money?” Pause to give the students a moment to think about the question, then say, “Let’s see what happened to a contestant on Who Wants to be a Millionaire?

 

Pause the video between 1:00 and 1:05 (before the audience’s answers are revealed) and have the class vote for the answer they think is correct. Don’t give the students too much time to think – you should simulate the time the contestant has to answer (about a minute.) Tally the votes on the board (and find the percentages) so the class can see the results. Compare the class percentages with the audience percentages. Now resume the video.

Stop the video at 2:18 so the correct answer is given, but the smaller squares are not yet revealed. Say, “Would you have lost $15,000 on this question like this contestant did? How do we know that 25 is the correct answer?” Help the students set up the problem.

25 (which is a square) is equal to (something squared) + (something squared)

So, 25 = x2 +y2

So, 52 = x2 +y2

“What formula is this?” [a circle]

“What does 52 represent?” [radius squared]

At this point you can draw the circle and the radius, then discuss how to find x2 and y2. This will lead to the formula for the Distance Formula!