Moving the green slider below will change the angle of rotation about the origin. Play with it for a bit and make some observations.
What observations did you make?
Move the slider to 90°. Then compare the coordinates of the original figure to the coordinates of the image. How are they similar? How are they different?
Move the slider to 180°. Then compare the coordinates of the original figure to the coordinates of the image. How are they similar? How are they different?
Move the slider to 270°. Then compare the coordinates of the original figure to the coordinates of the image. How are they similar? How are they different?
Move the slider to 360°. Then compare the coordinates of the original figure to the coordinates of the image. How are they similar? How are they different?