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 extend to the circle's circumference.

Front

What is an inscribed angle?

Back

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

Front

How is the measure of an inscribed angle related to the arc it intercepts?

Back

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

Front

What is the formula for the circumference of a circle?

Back

C = 2πr, where r is the radius.

Front

What is the relationship between the diameter and radius of a circle?

Back

The diameter is twice the length of the radius (D = 2r).

Front

What is a chord in a circle?

Back

A line segment whose endpoints lie on the circle.

Front

What is a secant line?

Back

A line that intersects a circle at two points.

Front

What is a tangent line?

Back

A line that touches a circle at exactly one point.

Front

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

Back

40°.

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.