answer
2.9 radians
step-by-step explanation
find the circumference = 2r pi
r = 2
c = 2 * 2 * pi = 4 pi
find the ratio of arc length to circumference
arc / c = 5.8/4 pi
this is equal to the ratio of radian measure / 2pi (since there are 2pi radian in a full circle)
5.8/4 pi = radian measure / 2pi
radian meaure = 5.8 * 2 / 4 = 2.9 radians