Circle Key Terms

A segment that connects any two points of the circle.

• chord

• diameter

• radius

• tangent

An arc of the circle that measures exactly 180 degrees.

• arc length

• major arc

• minor arc

• semicircle

A segment drawn from the center to any point of the circle.

• chord

• diameter

• radius

• secant

A segment that joins two points of the circle and passes through its center. It is known as the longest chord of a circle.

• chord

• diameter

• radius

• tangent

An arc of a circle that measures less than 180 degrees.

• semicircle

• minor arc

• major arc

• curve

A line drawn from the exterior of the circle which intersects the circle at exactly one point.

• chord

• secant

• tangent

• diameter

An angle formed in the interior of the circle whose vertex is at the center and the sides contains radii of the circle.

• vertical angle

• complementary angle

• central angle

• inscribed angle

An arc of the circle which measures greater than 180 degrees.

• minor arc

• major arc

• semicircle

• arc length

An angle formed in the interior of the circle whose vertex is a point of a circle and the sides are chords of the circle.

• central angle

• vertical angle

• inscribed angle

• supplementary angle

A line that intersects the circle at two points and contains chord of a circle.

• chord

• diameter

• tangent

• secant