CK-12 Geometry - Second Edition

10.4. Circumference and Arc Length http://www.ck12.org

10.4 Circumference and Arc Length

Learning Objectives

• Find the circumference of a circle.


• Define the length of an arc and find arc length.

Review Queue

1. Find a central angle in that interceptsCÊ


2. Find an inscribed angle that interceptsCÊ.


3. How many degrees are in a circle? FindmECD̂.


4. IfmCÊ= 26 ◦, findmCD̂andm^6 CBE.

Know What?A typical large pizza has a diameter of 14 inches and is cut into 8 or 10 pieces. Think of the crust as
the circumference of the pizza. Find thelengthof the crust for the entire pizza. Then, find the length of the crust for
one piece of pizza if the entire pizza is cut into a) 8 pieces or b) 10 pieces.

Circumference of a Circle

Circumference:The distance around a circle.