A figure that moves about a fixed point called the center of rotation. All the vertexes must move around the point of rotation (in this case the origin but could be any spot) they all must have the same degree of rotation and direction. Each vertex must be the same distance from the center. Pre-image ABCDEF is rotated around the origin and makes the image A'B'C'D'E'F'. If you where to find the point of rotation not on a graph and you have the image ABCDEF and you already image A'B'C'D'E'F' you have too draw a line connecting two points from each image and do that again with two different points. Use a compass and draw twp arches between the points and draw lines through the intersections and where the two new lines intersect is your point of rotation and using a protractors to measure the angle of the rotation. Its written as R [sub]origin 180[math]^\circ[/math][/sub]