Inscribed and Central Angles

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 a central angle?

Back

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

Front

How do you calculate the measure of an inscribed angle?

Back

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

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 a major arc?

Back

A major arc is an arc that measures greater than 180 degrees.

Front

What is a minor arc?

Back

A minor arc is an arc that measures less 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 AB is 68 degrees, what is the measure of the inscribed angle that intercepts arc AB?

Back

34 degrees (half of 68 degrees).

Front

If a central angle measures 90 degrees, what is the measure of the intercepted arc?

Back

90 degrees (equal to the central angle).

Front

What is the formula for finding the measure of an angle formed by two intersecting chords?

Back

The measure of the angle is equal to half the sum of the measures of the intercepted arcs.