CPM Homework Help : PC Problem 1-147

Hint (a):

Make a ratio comparing a half circle in degrees and radians.

Answer (a):

$\frac{\pi\ \text{radians}}{180\degree} = \frac{x}{120\degree}$

$120\degree\ \frac{\pi\ \text{radians}}{180\degree} =x$

$\frac{2}{3}\ \pi\text{ radians} = x$

Hint (b):

Follow a similar process as (a).

Hint (c):

Follow a similar process as (a).