The geometry of circles is very important in a number of fields and applications.

paint palette

Artists use the symmetry present in circles to create aesthetically pleasing paintings, sculptures, and other works of visual art.

nautilus shell

Circular shapes are present in nature and sciences such as chemistry and physics.

radio tower

Radio stations broadcast signals in a roughly circular radio pattern, and airlines use circles to plan route maps to fly between two cities in the shortest possible distance.


In this lesson, you will use important attributes of angles and segments found in circles in order to make conjectures and then use deductive reasoning to prove that the conjectures are true.

Important parts of a circle include the following: