This applet allows students to visualize the points rotating around the origin as well as around a specific vertice. This applet was made for 7th grade students.
With each rotation, what happens to the coordinates of A', B', and C' compared to the points A, B, and C? With each movement upon the slider Beta, what happens to the coordinates of A'1, B'1, and C'1 compared to the points A, B, and C? What happens when either slider has rotated 360 degrees? What meaning does moving 360 degrees around a specific point have?