Find the Radian Measure of the Central Angle of a Circle

Multiple Choice

Find the radian measure of the central angle of a circle of radius r that intercepts an arc of length s. ?
Radius r
Arc Length s
80 kilometers
?145 kilometers
?

A) ? = ?6 radians
B) ? = $\frac { 29 } { 45 }$ radians
C) ? = $\frac { 45 } { 29 }$ radians
D) ? = $\frac { 29 } { 16 }$ radians
E) ? = ? $\frac { 16 } { 29 }$ radians