Perimeter (circumference) of an Ellipse

The total distance around the line that forms the ellipse
When the circumference of a circle is so easy to find, it comes as a surprise that there is no easy way to find the circumference of an ellipse. There is simply no easy way to do it. Calculating it precisely requires the use of calculus, and is beyond the scope of this volume. If the ellipse has equal major and minor axes, it is a circle and the circumference is obvious.

Other ellipse topics