Lesson Summary: By the end of this lesson, one should be able to graph an ellipse given an equation and be able to write the equation of an ellipse given some information. Furthermore, one should be aware that a, b, and c are present in an ellipse. a is always the larger number under either x or y in the equation. C is equal to the square root of a^2 -b^2 and B is equal to a^2 - c^2. Furthermore, the foci will always be located on the major axis (the larger axis) equal to 2a. There is also a minor axis (the shorter axis) which is equal to 2b. The center is the midpoint of either the vertices located on the major or minor axis. A is the distance from the center to a vertices on the major axis, b is the distance from the center to a vertices on the minor axis, and c is the distance from the center to one of the foci.