a counterclockwise rotation about the origin of 90°
The coordinates of P(3, 3), Q(5, 3), R(5, 7)
The coordinates of P'(- 3, 3 ), Q'(- 3, 5), R'(- 7, 5)
Note that the y-coordinate of the image is the negative of the original, while the x-coordinate of the original becomes the y-coordinate of the image
The rotation which does this is a counterclockwise rotation about the origin of 90°
a point (x, y ) → (- y, x )
