SAT Math Multiple Choice Practice Question 529: Answer and Explanation

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Question: 529

7. If a circle has an area that is half its circumference, what is its radius?

B. 1
C. 4
D. π
E. 2π

Correct Answer: B


B Plugging In The Answers is the easiest way to solve this problem. If the radius is 4, then the area, πr2, is 16π, and the circumference, 2πr, is 8π. The area using the value in C is twice the circumference, not half. In order to make the area smaller, try B. If the radius is 1, then the area is π and the circumference is 2π. This is what the problem asks for! B must be the correct answer.

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