[header] How to graph a circle [title] Note the center of the circle. [step] The center is the point inside the circle that is at an equal distance from all of the points on the line. [title] Know how to find the radius of a circle. 
[step] The radius is the common and constant distance from all points on the line to the center of the circle. In other words, it is any line segment that joins the center of the circle with any point on the curved line.