3
Answer: CSet 1: Circles (Intermediate)
Explanation
PROBLEM
A circle has area 25pi. What is its radius?
A circle has area 25pi. What is its radius?
A.
7
B.
6
C.✓ Correct
5
D.
10
Detailed Explanation
Choice C is the best answer. A = pi times r squared. 25pi = pi times r squared. r squared = 25. r = 5
Why others are wrong:
A: 7 is incorrect because it does not satisfy the equation.
B: 6 is incorrect because it does not satisfy the equation.
D: 10 is incorrect because it does not satisfy the equation.