Coming up with the definition of a circle.
What is length of the radius? The distance between the center and a point on the circle. The distance stays the same. Try for a few circles by moving the slider. For each circle, try a few points on the circle (move X).
Three Reflection Lemma for Transformations
Find the three reflections that takes the first triangle to the second triangle.[br]Make sure that your construction is not distructable easily. (If I move the triangles, the construction should still work.)[br]Write out the proof of lemma. (You will need the three points transformation lemma.)
Tiling
Smiley, Move the slider back and forth.
Move the slider to see the animation.