Trig Question

What is the measure of the central angle of a circle if the radius is 18 centimeters. Assume that it intercepts a 12pi centimeter arc. I would prefer the answer in degrees if you dont mind.

Hello John!

$b=\frac{\pi r \alpha}{180^0}\\ \alpha=\frac{b\cdot 180^0}{\pi r}=\frac{12cm\cdot \pi \cdot180^0}{\pi\cdot18cm}$

$\alpha=120^0$

  !