4.3+Making+Copies

A.R. November 12, 2008 Block C Math Day 29, Grade. 7

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 Many things in our world are mathematically similar and we can use this to understand and describe the world around us. ======

EQ 4/5 What types situations can I use my similarity ideas to solve?
Problem 4.3 and Follow Up

A. **Can Raphael make a poster that is similar to his original ad on any of the three paper sizes-without having to trim off part of the paper? Why or why not?** Raphael can make a poster that is similar to his original ad without having to trim off part of the paper. He can make his original ad and make it 8.5 by11 through the copy machine. He can’t make his original ad to 11 by 14 or 11 by 17 because those sizes are too big.

B. **If you were Raphael, what paper size would you use to make a larger, similar poster on the copy machine?** What scale factor-expressed as a percent-would you enter into the copy machine? If I were Raphael, I would use 11 by 14 paper size. As a percent I would enter 130 percent. I would do this because it is the one which I will have to trim off only a little bit.

Problem 4.3 F.U:

1. **How would you use the copy machines described in the problem to reduce a drawing to 25% of its original size? Remember, the copy machines only accept values between 50% and 200%.** First I would make a 50% enlargement of the original copy. Then I would take the 50% enlargement of the original copy, and make a 50% copy of that. Hence, leaving me with a 25% copy. 100%(1/2) = 50%; 50%(1/2) = 25%.

2. **How would you use the copy machines to reduce a drawing to 12.5% of its original size?** I would continue the same procedure of the last one and then make a 50% enlargement of the 25% copy.


 * 3. How would you use the copy machines to reduce a drawing to 36% of its original size?** First I would make a 50% enlargement of the original copy. Then I would take the 50% enlargement of the original copy and make a 72% copy of that. Hence, leaving me with a 36% cop