5.1+Using+Shadows+to+Find+Heights

December 6, 2008 Lamisa Haque Math 7b __Big Idea__ Many things in our world are mathematically similar and we can use this to understand and describe the world around us. Essential Question # 4/5 - What types situations can I use my similarity ideas to solve?

Length of meterstick: 1 m Length of the meterstick's shadow: 0.2 m Length of the building's shadow: 7 m** First we had to find the scale factor from the shadow of the meterstick to the shadow of the building. We did this by dividing 7m (shadow of building) with 0.2m (shadow of meterstick) and we got 35, so that is the scale factor. This means that the height of the building is 35 m.
 * Mr. Anwar's class is using the shadow method to estimate the height of their school building. They have the following measurements and sketch:
 * A. Use what you know about similar triangles to find the building's height from the given measurements. Explain your work.**

Mr. Cooper said to make a random estimate. My partner and I said 12 meters. Then we made a sketch like this:  ||  ||
 * B. With your class, choose a building or other tall object. Work with a group to estimate the object's height using the shadow method.**

Our procedure was: 1. Measure Shadow A. 2. Measure Shadow B.  3. Come back to class. 4. Calculate the scale factor from A to B. 5. Use what we know to calculate C.

So we went and got the measurements. Here they are: Shadow A: 1.08 m Shadow B: 12.72 m Then we calculated the scale factor from A to B and we got 11.78. Therefor, it means that the height of the the building was 11.78. Scale factor: 11.78 m Height of C: 11.78 m __ Follow Up __ We never made a line plot so I could not put it on here.