3
Answer: BSet 4: Circles (Intermediate)
Explanation
PROBLEM
A circle has area 64pi. What is its radius?
A circle has area 64pi. What is its radius?
A.
16
B.✓ Correct
8
C.
9
D.
7
Detailed Explanation
Choice B is the best answer. A = pi times r squared. 64pi = pi times r squared. r squared = 64. r = 8
Why others are wrong:
A: 16 is incorrect because it does not satisfy the equation.
C: 9 is incorrect because it does not satisfy the equation.
D: 7 is incorrect because it does not satisfy the equation.