7

Set 1: Circles (Intermediate)

Explanation

Answer: C

PROBLEM

A circle has circumference 16pi. What is its radius?

A circle has circumference 16pi. What is its radius?

A.

4

B.

16

C.

8

✓ Correct
D.

6

Detailed Explanation

Choice C is the best answer. C = 2 times pi times r. 16pi = 2 times pi times r. r = 8

Why others are wrong:
A: 4 is incorrect because it does not satisfy the equation.
B: 16 is incorrect because it does not satisfy the equation.
D: 6 is incorrect because it does not satisfy the equation.