Question

Find a central angle (in radians) of a circe of radius 2 inches if the angle subtends an arc of 8 inches?

Answer 1

What you should know is that the length of an arc comes by:
arc = r * angle
Where
r = radio
angle = is the angle
Clearing the angle we have then:
angle = arc / r
angle = (8) / (2)
angle = 4 randians