Wednesday, November 19, 2008

Stretching and Shrinking Unit Project

Name ________________ Date ________

7th Grade Stretching and Shrinking Performances of Understanding


You will complete the following 3 tasks to demonstrate your understanding of the Stretching and Shrinking unit, and specifically of these 3 concepts:

1. Similarity
2. Scale factor
3. Setting up and solving proportions.

Refer to the link http://connectedmath.msu.edu/parents/ss/help/7/stretching/concept.pdf and your book for problems that we have done in class and homework for help.

All of your must be completed neatly on a poster. Be ready to present your work after Thanksgiving Holiday, i.e. December 1st, 2008.

You will be assessed on your knowledge and understanding of the concepts we have studied in this unit as well as your presentation. See checklist below each task for point values.

Your presentation will be assessed on:

_______ Creativity (4 points)

_______ Preparedness (4 points)

_______ Neatness (4 points)

_______ Ability to communicate math concepts (4 points)

_______ Visual Elements (4 points)




1.) Pick any 2-dimensional figure. Draw a model (either enlarged or reduced) of that figure. The model must be mathematically similar to the original figure. You must be able to present the original figure and the model, showing the mathematical similarities that exist between them visually.

________ Original figure and model are shown (2 points)

________ Original figure and model are mathematically similar (5 points)

2.) Find 3 pairs of figures that are mathematically similar to each other in your everyday life. Take pictures of them and write descriptions proving how they are mathematically similar. You may send digital copies of the pictures to me if you cannot print them out. My email is Skanchwala@bmsonline.org. OR you may draw the 3 pairs of figures if you do not have access to a camera.

__________ 3 pairs of figures (6 pictures total) are shown (3 points)

__________ Description showing each pair is mathematically similar. Include scale factor and proportions to show this. (10 points)

3.) Pick a tall building or structure in your neighborhood or town. Using the shadow or mirror method, find the height of the building by setting up two similar triangles. Draw them out and set up a proportion to show what the height of the building would be according to your method.

_________ Building is identified and represented either by a picture or drawing (2 points)

_________ Two similar triangles are drawn to represent proportional heights (2 points)

__________ Proportion is set up correctly and solved using either the scale factor method of cross-multiplication to find a close approximation of the building’s or tall structure’s height (5 points)

4.) Using an atlas or a map from the Internet, pick any place in the world that you would like to visit, and using the map scale, calculate the distance from San Francisco, California to the destination of your choice. Include the map and calculation on your poster.

__________ Map used is on poster (2 points)

__________ Calculations are shown to figure out approximate distance (5 points)

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