Ellipses

Symmetry

Ellipses have both reflectional and rotational symmetry. The reflectional symmetry of every ellipse is a vertical line through the center and a horizontal line through the center. The rotational symmetry of every ellipse is 180 degrees about the center point.

Example
State the symmetry for the ellipse modeled by the equation:

EllispeRevised1



Step 1. State the center.

The center of the ellipse is (-2, 5)

Step 2. State the reflectional symmetry.

This ellipse has lines of symmetry at x = -2 and y = 5.

Step 3. State the rotational symmetry.

This ellipse has 180 degree rotational symmetry about (-2, 5).