Circle

Circle

A circle is a curve consisting of all those points of a plane that lie at a fixed distance from a particular point in the plane, this point being the center.
The radius is the length of a line drawn from any point on the circle to the center point. The diameter, which is twice the radius, is the length from one point on the circle, through the center point, to another point on the circle.
A circle is a special case of an ellipse produced by a section perpendicular (at right angles) to the axis. [RA] {EB}