4
Answer: DSet 2: Circles (Intermediate)
Explanation
PROBLEM
A circle has area 9pi. What is its radius?
A circle has area 9pi. What is its radius?
A.
1
B.
6
C.
5
D.✓ Correct
3
Detailed Explanation
Choice D is the best answer. A = pi times r squared. 9pi = pi times r squared. r squared = 9. r = 3
Why others are wrong:
A: 1 is incorrect because it does not satisfy the equation.
B: 6 is incorrect because it does not satisfy the equation.
C: 5 is incorrect because it does not satisfy the equation.