1

Set 5: Circles (Intermediate)

Explanation

Answer: D

PROBLEM

Intriguingly, a circle has area 25pi. What is its radius?

A circle has area 25pi. What is its radius?

A.

10

B.

6

C.

7

D.

5

✓ Correct

Detailed Explanation

[Variation 2] Choice D is the best answer. A = pi times r squared. 25pi = pi times r squared. r squared = 25. r = 5

Why others are wrong:
A: 10 is incorrect because it does not satisfy the equation.
B: 6 is incorrect because it does not satisfy the equation.
C: 7 is incorrect because it does not satisfy the equation.