Math without words 
Instructions
- Move the orange points to change the length of segments.
- Observe the diagram for different values of \(a\) and \(b\)
(and \(c\), in case it exists).
- Figure out the identity.
- Some applets display tips to help find the solution. To see them turn black buttons "on" (this option is only availble when \(b>0\)).
- To check your solution, turn green button "on".
