Circle

A circle is the set of all points in a plane that are at a fixed distance from a fixed point called the center.

Definition

Standard Equation

Example: Standard Form

General Equation

Example: Finding Center and Radius

Point on a Circle

Practice Problems

1. Write the equation of a circle with center and radius .
2. Find the center and radius of .
3. Check if lies on .
4. Find the equation of a circle with center passing through .