Parallelogram? Why So? (GoGeometry Action 77)
- Tim Brzezinski
Creation of this applet was inspired by a post from Antonio Gutierrez (GoGeometry). Feel free to move any of the LARGE POINTS wherever you'd like. The outer green points control the orientation of the inner white points with which they're collinear. How can we formally prove that the quadrilateral formed is always a parallelogram?