We can find this using the formula for arc length (where [tex] r [/tex] is the radius of the circle and [tex] \theta [/tex] is the central angle in radians):
[tex] \textrm{Arc Length} = r\theta [/tex]
In our problem, we are given [tex] 12 = 8\theta [/tex]. This means that:
[tex] \theta = \dfrac{12}{8} = \boxed{\frac{3}{2}} [/tex]
The measure of the angle is 1.5.
