1. Move point E
2. Move point F
3. Watch the trace created.

1. What shape do the traces of points E and point F create?
2. What is the vertex of the trace of E?
3. What is the vertex of the trace of F?
4. Based on your pervious investigation, what would be call points A and B?
5. Find the difference between AE and EB then find the difference between AF and FB.
6. Move points E and F again, what do you notice about the differences you found in question 5?