# Definition:Circumcircle of Triangle

## Definition

The **circumcircle of a triangle** is the circle that passes through all three of the triangle's vertices.

This circle is said to circumscribe the triangle.

### Circumcenter

The center of a circumcircle of a triangle is called a **circumcenter of a triangle**.

### Circumradius

A radius of a circumcircle of a triangle is called a **circumradius of a triangle**.

In the above diagram, $R$ is a circumradius.