Central & 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 (rays) extend to the circumference of the circle.

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

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 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.

Front

If the measure of arc AB is 100°, what is the measure of the inscribed angle that intercepts arc AB?

Back

The measure of the inscribed angle is 50°.

Front

If the measure of a central angle is 72°, what is the measure of the arc it intercepts?

Back

The measure of the arc is also 72°.

Front

What is the formula to calculate the measure of an arc?

Back

The measure of an arc can be calculated using the formula: Arc Measure = Central Angle Measure.

Front

If arc XY measures 120°, what is the measure of the inscribed angle that intercepts arc XY?

Back

The measure of the inscribed angle is 60°.

Front

What is the sum of the measures of the angles around a point?

Back

The sum of the measures of the angles around a point is 360°.