Intro Circles Vocab

An arc of a circle whose endpoints are the endpoints of a diameter.

• semicircle

• major arc

• minor arc

• circle

An angle whose vertex is the center and whose sides are the radii of the circle.

• radius

• arc

• central angle

• secant line

A line segment whose endpoints are on a circle.

• semicircle

• concentric circles

• chord

• sector of a circle

An angle whose vertex is on the circle and whose sides are chords of the circle.

• adjacent arcs

• diameter

• Inscribed angle

• arc

A line that intersects a circle in exactly two points.

• diameter

• central angle

• arc

• secant line

An arc that is smaller than a semicircle.

• radii

• minor arc

• tangent line

• central angle

A line that intersects a circle in exactly one point.

• tangent line

• arc

• radius

• diameter

A line segment that has one endpoint on a circle and the other endpoint at the center of the circle.

• circle

• central angle

• radius

• arc

An arc that is larger than the semicircle.

• semicircle

• circle

• major arc

• adjacent arcs.

Is the red line a radius or diameter of the circle?

• Radius

• Diameter