Glencoe Math: Course 3, Volume 2
GM
Glencoe Math: Course 3, Volume 2 View details
6. Changes in Dimensions
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Exercise 24 Page 648

If Solid X is similar to Solid Y by a scale factor, then the surface area of X is equal to the surface area of Y times the square of the scale factor.

C

Practice makes perfect

We are given two similar solids.

The pyramids
We want to find the ratio of the surface area of the larger pyramid to the smaller pyramid. Let's start by calculating the ratio of their corresponding edge lengths.

25/15 = 5/3 We got that the dimensions of the larger pyramid is larger by a scale factor of 53 than the dimensions of the smaller pyramid. Next, let's recall the relationship between the surface areas of similar solids.

Surface Area of Similar Solids

If Solid X is similar to Solid Y by a scale factor, then the surface area of X is equal to the surface area of Y times the square of the scale factor.

Therefore, to get the surface area of the larger pyramid, we need to multiply the surface area of the smaller pyramid by 53 raised to the second power. S.A. of the larger pyramid = ( 5/3 )^2 ( S.A. of the smaller pyramid) We can rewrite this equation to get the ratio of the surface area of the larger pyramid to the smaller pyramid.
S.A. of the larger pyramid = (5/3 )^2 (S.A. of the smaller pyramid)
S.A. of the larger pyramid/S.A. of the smaller pyramid = (5/3 )^2
Simplify right-hand side
S.A. of the larger pyramid/S.A. of the smaller pyramid = 5^2/3^2
S.A. of the larger pyramid/S.A. of the smaller pyramid = 25/9
We got that the ratio of the surface area of the larger pyramid to the smaller pyramid is 259. This means that the correct option is C.