What is the relationship between the arc length and the radius of a circle when the central angle is defined in radians?

Question

anonymous · Answer

A.
The length of the arc intercepted by the central angle is equal to the radius of the circle.
B.
The length of the arc intercepted by the central angle is proportional to the radius of the circle.
C.
The length of the arc intercepted by the central angle is equal to the square root of the radius of the circle.
D.
The length of the arc intercepted by the central angle is not related to the radius of the circle.