Short presentation

The goal: an intelligent dynamic geometry program

-able to simulate on the computer the ruler and compass paradigm

-able to drag elements on constructions while keeping established relations among geometric objects

- omniscent (as a teacher!!) regarding facts about the geometric constructions

-enhanced features (geometric locus, 3D, web access, etc.)

First versions around 2000

Authors: F. Botana http://rosalia.uvigo.es/fbotana/

J.L. Valcarce

Several similar and recent attempts...Geometry Expert, Cinderella, Geother...but, of course , GDI is endowed with some unique features...

¥ Given a triangle ABC, a point X, its symmetrical points with respect to the sides, say, M,N,P, ....... then points M, N, P are they aligned?