See also:

• Kids and Teens: School Time: Math: Trigonometry  (9)
• Science: Math: Algebra: Geometric Algebra  (9)
• Science: Math: Recreations: Specific Numbers  (166)

Archimedes' Book of Lemmas  www.cut-the-knot.org/Curriculum/Geometry/BookOfLemmas/index.shtml A collection of all 15 propositions from Archimedes' Book of Lemmas with complete proofs, each accompanied by a Java illustration.

Bette Veteto's Homepage  www.people.memphis.edu/~brveteto History of Mathematics, very strong on geometry.

Bob's Pages  members.ozemail.com.au/~llan 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.

The Complete Quadrilateral  www.cut-the-knot.org/ctk/CompleteQuadrilateral.shtml Several properties of the complete quadrilateral illustrated with Java applets

Conjectures Produced by the Program Graffiti  cms.dt.uh.edu/faculty/delavinae/research/wowref.htm Graffiti is a computer program that makes conjectures in mathematics and chemistry. Links to the conjectures and bibliography.

Cuboid and Cube Surface Distances  www.btinternet.com/~se16/js/cuboid.htm A java applet with substantial analysis related to distances on a rectangular box.

Cut the Knot  www.cut-the-knot.org/geometry.shtml Features articles about specific problems, illusions, and puzzles. Includes diagrams.

Encyclopedia of Triangle Centers  faculty.evansville.edu/ck6/encyclopedia By Clark Kimberling. Over 1000 triangle centres in a searchable compilation with diagrams.

The Entropy Reduction Laboratory by Karl-Dietrich Neubert  www.neubert.net Discusses double shell structured periodic systems, platonic spheres, molecular and crystal structures, and FlashSort algorithms.

Erich's Packing Center  www.stetson.edu/~efriedma/packing.html Graphics and links for various packing, tiling and covering problems.

Fundamentals of Geometry  polly.phys.msu.ru/~belyaev/geometry.htm 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  www.geom.uiuc.edu/apps/gallery.html At the Geometry Center.

Geometric Group Theory  www.math.ucsb.edu/~jon.mccammond/geogrouptheory Information and resources about geometric group theory and low-dimensional topology. People, groups, meetings, links.

Geometry Activities  homepage.mac.com/efithian/geometry.html By Ephraim Fithian.

Geometry and the Imagination in Minneapolis  www.geom.uiuc.edu/docs/doyle/mpls/handouts/handouts.html 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  www.geom.uiuc.edu 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  www.geom.uiuc.edu/docs/reference/CRC-formulas 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  agutie.homestead.com 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  www.ics.uci.edu/~eppstein/geom.html Includes collections from various areas in which ideas from discrete and computational geometry meet real world applications.

The Geometry Junkyard  www.ics.uci.edu/~eppstein/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  www.cut-the-knot.com/geometry.html 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  www.math.msu.edu/gt Activities of the geometry/topology group at Michigan State University.

GLaD Comments  jwilson.coe.uga.edu/Texts.Folder/GLaD/GLaD.Comments.html A new type of geometric construction that was discovered by Dan Litchfield and David Goldenheim. Includes general explanation and sketch examples.

Go Geometry  www.gogeometry.com 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  www.math.pitt.edu/~thales/kepler98 Information on the recent proof of Kepler conjecture on sphere packings.

The Lepidoptera of the Circles  www.cut-the-knot.org/ctk/Lepidoptera.shtml The Butterfly theorem and its generalizations illustrated by Java applets.

Math 3210 - Higher Geometry I  www-math.cudenver.edu/~wcherowi/courses/m3210/m3210.html Course notes by Bill Cherowitzo.

Math Forum: Geometry.research  mathforum.org/kb/forum.jspa?forumID=130 Discussion board for geometry professors and instructors to keep informed of the latest research.

Math Forum: Search geometry-forum  mathforum.org/kb/forum.jspa?forumID=126 Those interested in examining the previous incarnation of the Math Forum may search the archives of the Geometry Forum.

Mathematical Curves and Surfaces  pagesperso-orange.fr/roger.assouly Graphical representations of computer generated forms. (French/English).

Morley's Miracle  www.cut-the-knot.com/triangle/Morley/index.html 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  www.javeriana.edu.co/universitas_scientiarum/universitas_docs/vol6n2/A… High school students solve complex geometric problems by using GLad Sketchpad. Page includes diagrams.

Packomania  hydra.nat.uni-magdeburg.de/packing/packing.html Includes packings of equal objects in containers together with source codes to obtain them numerically.

Paul Bourke's Geometry Page  astronomy.swin.edu.au/~pbourke/geometry Includes formulas, definitions and three dimensional image illustrations.

Polyedergarten  www.polyedergarten.de Shows paper models of polyhedra.

Problem of the Minimum Rotation Surface  home.imm.uran.ru/iagsoft/PMRS_J.html Java applet demonstrating the catenary.

Sangaku: Reflections on the Phenomenon  www.cut-the-knot.org/pythagoras/Sangaku.shtml Critical reflections on the sangaku phenomenon accompanied by a collection of solved sangaku problems, many with interactive Java illustrations.

Steiner Surfaces  www.ipfw.edu/math/Coffman/steinersurface.html Mathematical descriptions and ray-traced images of various types of Steiner surfaces.

Tim Lister's Hyperbolic Geometry  mcs.open.ac.uk/tcl2/nonE/nonE.html Cabri constructions for the demonstration of the basic concepts of hyperbolic geometry in the Poincare disc model.

Wilson Stothers' Inversive Geometry and CabriJava Pages  www.maths.gla.ac.uk/~wilson/cabripages/inversive/inversive0.html Includes Steiner's Porism and the arbelos.

Xah's Personal Page  xahlee.org/PageTwo_dir/more.html 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  www.npr.org/templates/story/story.php?storyId=4531695 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 mathematicians talk with NPR's Jacki Lyden about hyperbolic crocheting. [4:47 streaming audio broadcast] (March 13, 2005)