Arcs and Central Angles

Front

What is an arc in a circle?

Back

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

Front

Define 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 intersect the circle.

Front

What is a minor arc?

Back

A minor arc is an arc that is smaller than a semicircle, measuring less than 180 degrees.

Front

What is a major arc?

Back

A major arc is an arc that is larger than a semicircle, measuring more than 180 degrees.

Front

How do you find the measure of an arc?

Back

The measure of an arc is equal to the measure of its corresponding central angle.

Front

What is the relationship between the central angle and the arc it intercepts?

Back

The measure of the arc is equal to the measure of the central angle in degrees.

Front

If the measure of arc AB is 140 degrees, what is the measure of the central angle AOB?

Back

The measure of the central angle AOB is also 140 degrees.

Front

What is the formula for finding the length of an arc?

Back

Arc length = (central angle/360) x (2πr), where r is the radius.

Front

What is the measure of a semicircle?

Back

The measure of a semicircle is 180 degrees.

Front

If arc KL measures 88 degrees, what is the measure of the central angle KOL?

Back

The measure of the central angle KOL is 88 degrees.