Circles: Arcs, Angles and Segments

Front

What is a circle?

Back

A circle is a set of points in a plane that are equidistant from a fixed point called the center.

Front

What is the radius of a circle?

Back

The radius is the distance from the center of the circle to any point on its circumference.

Front

What is the diameter of a circle?

Back

The diameter is twice the length of the radius and is the longest distance across the circle.

Front

What is a chord in a circle?

Back

A chord is a line segment whose endpoints lie on the circumference of the circle.

Front

What is an arc in a circle?

Back

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

Front

What is a central angle?

Back

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

Front

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

Back

The measure of a central angle is equal to the measure of its intercepted arc.

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.

Front

What is the relationship between an inscribed angle and its intercepted arc?

Back

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

Front

What is a tangent to a circle?

Back

A tangent is a line that touches the circle at exactly one point.