# Thebault Action!!!

- Author:
- Tim Brzezinski

- Topic:
- Geometry, Parallelogram, Square

The following applet illustrates

**Thebault's Theorem**without words, segment lengths, or angle measures. Interact with the following applet for a few minutes. Be sure to change the locations of the quadrilateral's**vertices**each time before sliding the slider. Without researching**Thebault's Theorem**on another tab in your internet browser, try to express this theorem in your own words as a conditional ("if-then") statement. How could you formally prove what this applet informally illustrates?*Creation of this applet was inspired by a tweet from Cliff Pickover.*