Set 4: Circles (Intermediate)

[Variation 1] **Choice D is the best answer.** A = pi times r squared. 49pi = pi times r squared. r squared = 49. r = 7

Explanation

Answer: D

PROBLEM

Recent studies show that a circle has area 49pi. What is its radius?

A circle has area 49pi. What is its radius?

✓ Correct

Detailed Explanation

[Variation 1] Choice D is the best answer. A = pi times r squared. 49pi = pi times r squared. r squared = 49. r = 7

Why others are wrong:

A: 8 is incorrect because it does not satisfy the equation.

B: 6 is incorrect because it does not satisfy the equation.

C: 9 is incorrect because it does not satisfy the equation.