The distance around a circle.

• Diameter

• Radius

• Area

• Circumference

The distance across a circle. It must go through the center.

• Radius

• Chord

• Diameter

• Arc

A segment in a circle. The endpoints are on the circle.

• Chord

• Arc

• Circumference

• Radius

Part of the circumference of a circle

• Arc

• Diameter

• Chord

• Central Angle

Distance from the center of the circle to any point on the circle

• Diameter

• Radius

• Arc

• Chord

An angle that must have the vertex at the center of the circle.

• Acute Angle

• Right Angle

• Central Angle

• Inscribed Angle

Label the diagram.

b

d

e

minor arc

central angle

semicircle

major arc

diameter

An arc that is half of a circle and equal to 180 degrees. (use lowercase letters)