3

Set 2: Circles (Advanced)

Explanation

Answer: B

PROBLEM

A circle has radius 3 and an arc length of 1.5pi. What is the central angle in degrees?

A circle has radius 3 and an arc length of 1.5pi. What is the central angle in degrees?

A.

89

B.

90

✓ Correct
C.

92

D.

180

Detailed Explanation

Choice B is the best answer. Arc = (angle/360) times 2 times pi times r. 1.5pi = (angle/360) times 6pi. angle = 90 degrees

Why others are wrong:
A: 89 is incorrect because it does not satisfy the equation.
C: 92 is incorrect because it does not satisfy the equation.
D: 180 is incorrect because it does not satisfy the equation.