7
Answer: ASet 1: Circles (Advanced)
Explanation
PROBLEM
A circle has radius 3 and an arc length of 3pi. What is the central angle in degrees?
A circle has radius 3 and an arc length of 3pi. What is the central angle in degrees?
A.✓ Correct
180
B.
181
C.
360
D.
178
Detailed Explanation
Choice A is the best answer. Arc = (angle/360) times 2 times pi times r. 3pi = (angle/360) times 6pi. angle = 180 degrees
Why others are wrong:
B: 181 is incorrect because it does not satisfy the equation.
C: 360 is incorrect because it does not satisfy the equation.
D: 178 is incorrect because it does not satisfy the equation.