**Rectangle**

Area = Length * Width

**Ellipse**

Area = Pi * A * B

Where Pi = 3.14159..

A = semi-major axis

B = semi-minor axis

Definitions:

**semi-major axis**: The major axis of an ellipse is its longest diameter.
The semi-major axis is one half of the major axis, and thus runs from the center
to the edge of the ellipse.
For the special case of a circle, the semi-major axis is just the radius.

**semi-minor axis**: The minor axis of an ellipse is the longest line that runs perpendicular to the major axis.
The semi-minor axis is one half of the minor axis.