Circles, arcs, angles

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

Define 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, passing through the center.

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.

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

State 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 chord in a circle?

Back

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

Front

Define a tangent to a circle.

Back

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

Front

What is the formula for the circumference of a circle?

Back

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