Given triangle ABC, [br]Move the points A, etc to vary the triangle. [br]Note the coordinates of the image vertices A' , etc. and the coordinates of the corresponding original Pts A, etc.

Are the triangles congruent? How do you know? [br]Move slider δ to 90°, then 180`. How is this different to a translation? Compare the coordinates of ABC to those of A'B'C'. [br]Change the angle of rotation; predict the coordinates of the new triangle. [br]Reflect the triangle across the x and y axes; compare the coordinates to those of the original. [br]Reflection: Compare and contrast translations, rotations and reflections. How does the resulting shape compare to the original? Will this always be true?