10) Given central angle is 120 degrees. Find angle AOB.

The diagram shows a central angle $$\angle AOB$$. The angle 120 degrees is indicated as the measure of the arc AB.

A central angle is an angle whose vertex is the center O of a circle and whose sides are radii intersecting the circle at two points A and B.

The measure of a central angle is equal to the measure of its intercepted arc.

Therefore, $$\angle AOB = \text{measure of arc } AB$$.

Given that the measure of arc AB is 120 degrees, then $$\angle AOB = 120^\circ$$.

The text below the diagram says "AOB - центральной", which means AOB is a central angle.

Ответ: 120°