Central and Inscribed Angles

Front

What is a central angle?

Back

An angle whose vertex is at the center of a circle and whose sides are radii that intersect the circle.

Front

What is an inscribed angle?

Back

An angle formed by two chords in a circle which have a common endpoint.

Front

How do you find the measure of a central angle?

Back

The measure of a central angle is equal to the measure of the arc it intercepts.

Front

How do you find the measure of an inscribed angle?

Back

The measure of an inscribed angle is half the measure of the arc it intercepts.

Front

What is a minor arc?

Back

An arc that measures less than 180 degrees.

Front

What is a major arc?

Back

An arc that measures more than 180 degrees.

Front

What is a semicircle?

Back

An arc that measures exactly 180 degrees.

Front

If the measure of arc AB is 80 degrees, what is the measure of the inscribed angle that intercepts arc AB?

Back

40 degrees.

Front

If the measure of a central angle is 60 degrees, what is the measure of the arc it intercepts?

Back

60 degrees.

Front

What is the relationship between a central angle and an inscribed angle that intercept the same arc?

Back

The central angle is twice the measure of the inscribed angle.