- The Math Forum — K–12 Geometry
- The Math Forum — College Geometry
- The Math Forum — Advanced Geometry
- Finitism in Geometry
- Geometry in the 19th Century
Geometry lessons in PowerPoint All lessons introduce mathematical concepts, step by step, with animations of text, points, lines and figures in general. Solution of problems is also given step by step. Colors are used to give hints and clues to follow the concept or the solution of the problems.