Central and Inscribed Angles

Front

What is a central angle?

Back

A central angle is an angle whose vertex is at the center of a circle and whose sides are radii that extend to the circumference.

Front

What is an inscribed angle?

Back

An inscribed angle is an angle formed by two chords in a circle which have a common endpoint. The vertex of the angle is on the circle.

Front

What is the relationship between a central angle and its intercepted arc?

Back

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

Front

What is the relationship between an inscribed angle and its intercepted arc?

Back

The measure of an inscribed angle is half the measure of its intercepted arc.

Front

Define a minor arc.

Back

A minor arc is an arc that is smaller than a semicircle, measuring less than 180 degrees.

Front

Define a major arc.

Back

A major arc is an arc that is larger than a semicircle, measuring more than 180 degrees.

Front

What is a semicircle?

Back

A semicircle is an arc that measures exactly 180 degrees.

Front

If the measure of arc ABC is 210°, what is the measure of the inscribed angle that intercepts arc ABC?

Back

The inscribed angle is 105°.

Front

What is the formula to find the measure of an inscribed angle?

Back

Inscribed angle = 1/2 * (measure of intercepted arc).

Front

If the measure of arc AB is 142°, what is the measure of the central angle that intercepts arc AB?

Back

The central angle is 142°.