Circle Geometry Terms

Front

Circumference

Back

The distance around the circle; a special name for the perimeter of the circle.

Front

Arc

Back

A part of the circumference.

Front

Radius

Back

A line segment that joins the center to the boundary/circumference of a circle.

Front

Chord

Back

A line segment which cuts the circle into two parts at the edge of the circle.

Front

Diameter

Back

The diameter is length of the line through the center that touches two points on the circle.

Front

Tangent

Back

A line that touches the circle at a single point on the circumference.

Front

Segment

Back

An area of the circle enclosed by the chord and an arc.

Front

Sector

Back

An area of the circle enclosed by two radii and an arc.

Front

Semicircle

Back

Half a circle, the area enclosed by the diameter and an arc.