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.

Front

What is an inscribed angle?

Back

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

Front

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

Back

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

Front

What is the formula for the circumference of a circle?

Back

C = 2πr, where r is the radius.

Front

What is the diameter of a circle?

Back

The distance across the circle through its center, equal to twice the radius.

Front

What is a chord in a circle?

Back

A line segment with both endpoints 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 radius of a circle is 3 cm, what is the circumference?

Back

C = 2π(3) = 6π cm.

Front

What is the measure of an inscribed angle if the central angle is 80°?

Back

40°.