Circles : Central Angles and Arcs

Front

What is a central angle in a circle?

Back

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

Front

How do you calculate the measure of a central angle?

Back

The measure of a central angle is equal to the measure of the arc it intercepts.

Front

What is an arc in a circle?

Back

An arc is a portion of the circumference of a circle.

Front

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

Back

The measure of the central angle is equal to the measure of the 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

How do you find the length of an arc?

Back

The length of an arc can be found using the formula: Length = (θ/360) * 2πr, where θ is the central angle in degrees and r is the radius.

Front

What is the formula for the circumference of a circle?

Back

The circumference of a circle is given by the formula: C = 2πr, where r is the radius.

Front

If the radius of a circle is 5 cm, what is the circumference?

Back

C = 2π(5) = 10π cm, approximately 31.42 cm.