Inscribed angleCenter angle given
The angle at the center is given. Find the angle on the circle.
When the angle at the center is given, the angle on the circle is half of it. These free printable worksheets ask for that one direction, eight times a page, so a student can get used to reading the figure before the two directions are mixed.
If they get stuck

The answer key prints on a separate page.
Each circle has two angles standing on the same arc. The one at the center carries a number, such as 130°, and the one on the circle carries a question mark. Half of 130° is 65°, and that is all the arithmetic there is. What takes practice is seeing that the two angles are a pair, because the theorem only applies to angles that stand on the same arc.
Some figures look quite different from others. A 30° angle at the center gives a narrow sliver, and a 170° angle almost reaches a straight line across the circle. The rule stays the same in both, and working through the two extremes on a page is a good way to believe it.
Center angle 30°, find the angle on the circle