2
Answer: BSet 1: Circles (Intermediate)
Explanation
PROBLEM
A circle has circumference 10pi. What is its radius?
A circle has circumference 10pi. What is its radius?
A.
4
B.✓ Correct
5
C.
6
D.
10
Detailed Explanation
Choice B is the best answer. C = 2 times pi times r. 10pi = 2 times pi times r. r = 5
Why others are wrong:
A: 4 is incorrect because it does not satisfy the equation.
C: 6 is incorrect because it does not satisfy the equation.
D: 10 is incorrect because it does not satisfy the equation.