Question square

3.1 Ratios, Rates, and Proportional Relationships - Scale factors in geometry
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Square X has a side length of 12 centimeters. The perimeter of square Y is 2 times the perimeter of square X. What is the length, in centimeters, of one side of square Y?

A.

6

B.

10

C.

14

D.

24

Square X has a side length of 12 centimeters. The perimeter of square Y is 2

Hard-difficulty · SAT Math · Ratios, Rates, and Proportional Relationships — Scale factors in geometry. Read the question above, select your answer, and check the full explanation below to understand exactly why the correct choice works.

Answer explanation

Choice D is correct. The perimeter, P , of a square can be found using the formula P = 4 s , where s is the length of each side of the square. It's given that square X has a side length of 12 centimeters. Substituting 12 for s in the formula for the perimeter of a square yields P=412, or P = 48 . Therefore, the perimeter of square X is 48 centimeters. It’s also given that the perimeter of square Y is 2 times the perimeter of square X. Therefore, the perimeter of square Y is 248, or 96 , centimeters. Substituting 96 for P in the formula P=4s gives 96=4s. Dividing both sides of this equation by 4 gives 24 = s . Therefore, the length of one side of square Y is 24 centimeters.

Choice A is incorrect and may result from conceptual or calculation errors.

Choice B is incorrect and may result from conceptual or calculation errors.

Choice C is incorrect and may result from conceptual or calculation errors.