This document is a lesson on rotations of 180 degrees. It discusses the rule for rotating a point (x,y) 180 degrees, which is that it maps to (-x,-y). Examples are given of rotating points and figures 180 degrees clockwise and counterclockwise. The lesson emphasizes that rotating 180 degrees clockwise or counterclockwise yields the same result. Practice problems have students rotating triangles and finding the images of points under a 180 degree rotation. Other rotation rules for 90 degrees are also stated.