Geometry Vocabulary

The distance around a circle

• radius

• circle

• diameter

• circumference

The distance across a circle through its center.

• chord

• diameter

• radius

• rule

Part of the circumference of a circle

• arc

• radius

• smile

• ray

An angle whose vertex is the center of a circle.

• central angle

• angle O

• inscribed angle

• exterior angle

A half circle

• squatcircle

• semicircle

• most of a circle

An angle that opens to the interior of the circle from a vertex on the circle.

• inside angle

• exterior angle

• inscribed angle

• central angle

A region bounded by an arc of a circle and two radii.

• Sector

• Chord

• Diameter

• Semicircle

A polygon whose vertices are on a circle and whose other points are inside the circle.

• inscribed polygon

• concentric circles

• circumscribed polygon

The distance between the pivot point and the marking point of a compass when drawing a circle.

• diameter

• radius

• chord

• arc

The point that is the same distance from any point on a circle.

• radius

• sector

• center

• angle