Circle



A circle is the set of all points in a plane where each point is equidistant from a single point called the center. The perimeter of a circle is called the circumference. The distance of a circle's width at its widest is called the diameter, while the distance between the circumference and the center is called the radius.

Standard Form of a Translated Circle
The equation of a circle is: $$(x - h)^2 + (y-k)^2 = r^2$$, where $$r$$ is the radius and $$(h,k)$$ is the center.