This is the form of a circle. Use this form to determine the center and radius of the circle.

Match the values in this circle to those of the standard form. The variable represents the radius of the circle, represents the x-offset from the origin, and represents the y-offset from origin.

The center of the circle is found at .

Center:

These values represent the important values for graphing and analyzing a circle.

Center:

Radius:

Graph x^2+y^2=81