3

Set 5: Circles (Beginner)

Explanation

Answer: B

PROBLEM

Intriguingly, a circle has radius 5. What is its circumference? (Express answer as a number times pi)

A circle has radius 5. What is its circumference? (Express answer as a number times pi)

A.

5pi

B.

10pi

✓ Correct
C.

25pi

D.

12pi

Detailed Explanation

[Variation 2] Choice B is the best answer. Circumference = 2 times pi times r = 2 times pi times 5 = 10pi

Why others are wrong:
A: 5pi is incorrect because it does not satisfy the equation.
C: 25pi is incorrect because it does not satisfy the equation.
D: 12pi is incorrect because it does not satisfy the equation.