2

Set 3: Circles (Intermediate)

Explanation

Answer: A

PROBLEM

Recent studies show that a circle has circumference 14pi. What is its radius?

A circle has circumference 14pi. What is its radius?

A.

7

✓ Correct
B.

5

C.

14

D.

8

Detailed Explanation

[Variation 1] Choice A is the best answer. C = 2 times pi times r. 14pi = 2 times pi times r. r = 7

Why others are wrong:
B: 5 is incorrect because it does not satisfy the equation.
C: 14 is incorrect because it does not satisfy the equation.
D: 8 is incorrect because it does not satisfy the equation.