- Sarah Barron
The rotation of figure ABCD 90 degrees counterclockwise about point E can be proven accurate without the use of a coordinate plane because each vertex in the pre-image ABCD was moved the same distance and direction around the center of rotation. Therefore, each vertex in the pre-image and image are the same distance from the center point. Since a rotation is a type of rigid motion, the shape and size of the figure was not altered. To prove this rotation, figure A’B’C’D’ can be mapped onto figure ABCD by a rotation of 90 degrees clockwise to show that it is an image of that figure.