If the circumference of a circle is 24, and the angle measure of an arc is 120o, which is the length of the arc?

The best way to solve this problem is to use proportions. That said, a circle's given arc length is proportional to the angle measure of that arc. So, 120degrees out of 360degrees total is one third (1/3) of the circle. Therefore, the arc length will be one third of the circle's circumference (24 • 1/3) which is 8.

The arc length is 8.