Geometry

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Archimedes' Book of Lemmas :

- A collection of all 15 propositions from Archimedes' Book of Lemmas with complete proofs, each accompanied by a Java illustration.
Bette Veteto's Homepage :

- History of Mathematics, very strong on geometry.
Bob's Pages :

- A collection of interactive geometry applets. Topics include polyhedra, Poncelet's porism, Soddy's hexlet, Mandelbrot set, Steiner porism, Pappus's chain, Repulsion polyhedra and stereo pictures.
Center of Points in 2- or Higher-dimensional Space :

- It provides important formulations for finding a center of points in 2 or higher dimensional space. It can be used in drawing delauney triagulation and voronoi diagram in two or higher dimensions. It also describes how many points are required in defining a center in n-dimensional space.
The Complete Quadrilateral :

- Several properties of the complete quadrilateral illustrated with Java applets
Conjectures Produced by the Program Graffiti :

- Graffiti is a computer program that makes conjectures in mathematics and chemistry. Links to the conjectures and bibliography.
Cuboid and Cube Surface Distances :

- A java applet with substantial analysis related to distances on a rectangular box.
Cut the Knot :

- Features articles about specific problems, illusions, and puzzles. Includes diagrams.
Encyclopedia of Triangle Centers :

- By Clark Kimberling. Over 1000 triangle centres in a searchable compilation with diagrams.
The Entropy Reduction Laboratory by Karl-Dietrich Neubert :

- Discusses double shell structured periodic systems, platonic spheres, molecular and crystal structures, and FlashSort algorithms.
Erich's Packing Center :

- Graphics and links for various packing, tiling and covering problems.
Fundamentals of Geometry :

- Free online book on geometry in pdf format. Contains material not easily found elsewhere from detailed exposition of elementary absolute geometry based on Hilbert's axioms to more advanced topics.
A Gallery of Interactive On-Line Geometry :

- At the Geometry Center.
Geometric Group Theory :

- Information and resources about geometric group theory and low-dimensional topology. People, groups, meetings, links.
Geometry Activities :

- By Ephraim Fithian.
Geometry and the Imagination in Minneapolis :

- Geometry exercises for a two-week summer workshop led by John Conway, Peter Doyle, Jane Gilman and Bill Thurston at the Geometry Center in Minneapolis, June 1991.
Geometry Center :

- Web site for the (now closed) Center for the Computation and Visualization of Geometric Structures at the University of Minnesota. Graphics, multimedia, software, teaching resources.
Geometry Formulas and Facts :

- Excerpts from the 30th Edition of the CRC Standard Mathematical Tables and Formulas (1995), namely, the geometry section minus differential geometry.
Geometry from the Land of the Incas :

- Presents problems involving circles and triangles, with proofs, SAT practice quizzes and famous quotes. Also, has examples of geometry in Peruvian culture.
Geometry in Action :

- Includes collections from various areas in which ideas from discrete and computational geometry meet real world applications.
The Geometry Junkyard :

- Usenet clippings, web pointers, lecture notes, research excerpts, papers, abstracts, programs, problems, and other stuff related to discrete and computational geometry.
Geometry Page from Interactive Mathematics Miscellany :

- Includes articles on topics in elementary and not so elementary geometry, many with interactive Java illustrations and multiple proofs.
Geometry/Topology at Michigan State University :

- Activities of the geometry/topology group at Michigan State University.
GLaD Comments :

- A new type of geometric construction that was discovered by Dan Litchfield and David Goldenheim. Includes general explanation and sketch examples.
Go Geometry :

- Offers a variety of resources for teaching and learning about geometry. Problems and theorems are presented with step-by-step solutions for each proof.
The Kepler Conjecture :

- Information on the recent proof of Kepler conjecture on sphere packings.
The Lepidoptera of the Circles :

- The Butterfly theorem and its generalizations illustrated by Java applets.
Math 3210 - Higher Geometry I :

- Course notes by Bill Cherowitzo.
Math Forum: Geometry POW/POM Search :

- Search the Geometry Problem of the Week's archive of creative, non-routine challenges, as well as submissions and commentary, dating back to 1993.
Math Forum: Geometry.research :

- Discussion board for geometry professors and instructors to keep informed of the latest research.
Math Forum: Search geometry-forum :

- Those interested in examining the previous incarnation of the Math Forum may search the archives of the Geometry Forum.
Mathematical Curves and Surfaces :

- Graphical representations of computer generated forms. (French/English).
Morley's Miracle :

- A discussion of Morley's famous theorem and the research of which it was a tiny part. 5 proofs are given including J. Conway's, D. Newman's, and A. Connes'.
New Mathematical Findings by Secondary Students :

- High school students solve complex geometric problems by using GLad Sketchpad. Page includes diagrams.
A New Way to Calculate a Triangle's Area :

- Using the length of the three sides. The proof is better understood than the old one.
Packomania :

- Includes packings of equal objects in containers together with source codes to obtain them numerically.
Paul Bourke's Geometry Page :

- Includes formulas, definitions and three dimensional image illustrations.
Polyedergarten :

- Shows paper models of polyhedra.
Problem of the Minimum Rotation Surface :

- Java applet demonstrating the catenary.
Sangaku: Reflections on the Phenomenon :

- Critical reflections on the sangaku phenomenon accompanied by a collection of solved sangaku problems, many with interactive Java illustrations.
Steiner Surfaces :

- Mathematical descriptions and ray-traced images of various types of Steiner surfaces.
Tim Lister's Hyperbolic Geometry :

- Cabri constructions for the demonstration of the basic concepts of hyperbolic geometry in the Poincare disc model.
Wilson Stothers' Inversive Geometry and CabriJava Pages :

- Includes Steiner's Porism and the arbelos.
Xah's Personal Page :

- Features an illustrated dictionary of special plane curves, a paper on wallpaper groups, mathematics image gallery and links to software packages.
NPR : Mathematicians Get Crafty with Geometry :

- A husband and wife from Cornell University have come up with a crafty way to illustrate high-level geometry concepts -- by manipulating yarn into models that help explain the curvature of spaces. The mathemeticians talk with NPR's Jacki Lyden about hyperbolic crocheting. [4:47 streaming audio broadcast] (March 13, 2005)