Lee Dickey's Geometry Corner

Geometry Corner

Three-Four-Five Triangle and the Golden Mean

The figure above, (click on it to see a larger version) shows how one may use the famous three-four-five triangle inscribed in a circle to construct the Golden Ratio. Of course this is not the most efficient construction in terms of the number of steps required, but it is interesting. It was discovered by Gabries Bosia. Find out more about constructions for the golden mean

Geometry

I am interested in Geometry, including finite geometric structures, like finite projective planes and finite hyperbolic planes.

Here are some very nice geometrical things.

The Math Forum at Swarthmore is doing wonderful things with geometry (and other areas of mathematics) these days.
Dynamic geometry hot topic in teaching and research. Two interesting archives are
- The Cabri Archives has some of my early geometrical constructions.
- Sketchpad Archives
A technical outline of paper called "On a Family of Conics" features a theorem about conics that was discovered using Cabri-Géomètre and Cabri Geometry II. The proof makes use of Maple, the symbolic algebra program. An earlier version of this paper, entitled Families of Conics is included as a "submission" to the Math Forum at Swarthmore College.
If you have Cabri Geometry II you can view the Families of Conics dynamically. Even if you don't have the complete version, you can get a demonstration version for two popular home computer systems:
- for MacOS
- for Dos or Windows
A great set of polyhedra from Magnus Wenninger, marvelous in their intricate detail and complexity.
Geometria and Polyhedron are interactive programs by Stelian Dumitrascu.
Henry Chasey's Polyhedra Model Collection. Sources in Long Island,New York .
Henry Chasey's Polyhedra Model Collection. Waterloo mirror site.
George Hart's Pavillion of Polyhedriality.
Tom Gettys' Polyhedra Hyperpages .
A collection of uniform polyhedra maintained by Roman Maeder.

This page is maintained by Lee Dickey. Send him an e-mail at "LJDickey@Math.UWaterloo.CA" or visit his home page .