3
Answer: ASet 1: Circles (Advanced)
Explanation
PROBLEM
A circle has radius 2 and an arc length of 1pi. What is the central angle in degrees?
A circle has radius 2 and an arc length of 1pi. What is the central angle in degrees?
A.✓ Correct
90
B.
92
C.
180
D.
45
Detailed Explanation
Choice A is the best answer. Arc = (angle/360) times 2 times pi times r. 1pi = (angle/360) times 4pi. angle = 90 degrees
Why others are wrong:
B: 92 is incorrect because it does not satisfy the equation.
C: 180 is incorrect because it does not satisfy the equation.
D: 45 is incorrect because it does not satisfy the equation.