Students will rotate a triangle about the origin and discover the rules for rotations of 90 and 180 degrees, as well as the relationship between the original points and the rotated points.

1) What are the coordinates of points A, B, and C?
2) Move the slider to rotate the triangle 90 degrees about the origin. What are the coordinates of A', B', and C'? Can you describe a rule for this rotation?
3) Move the slider to rotate the triangle 180 degrees about the origin. What are the coordinates of A', B', and C'? Can you describe a rule for this rotation?
4) What do you notice about the relationship between the original point, the rotated point, and the angle of rotation? Does this rule hold true for the other two points? Rotate the triangle by either 90 or 180 degrees and create an angle between B and B' and C and C' to test your conjecture.