Geometry is the study of shapes and configurations. It attempts to understand and classify spaces in various mathematical contexts. There are many different types of geometry such as Euclidean Geometry, Riemannian Geometry, Gravitational Lensing, Differential Geometry, Algebraic Geometry, Semi-Riemannian Geometry and Symplectic Geometry.

Free Math Help - A nice collection of geometry lesson, many on video, as well as a list of formulas and a geometry message board where you can ask questions and receive answers.

Areas, Volumes, Surface Areas - Includes illustrations with formulas of the volume, area, and surface area of many different shapes.

The Geometry Center - A mathematics research and education center at the University of Minnesota. K-16 math education available, including help learning geometry. Workshops, seminars and courses are available.

Geometry - Math for Morons - Everything from parallel lines to volumes of prisms and a couple of word problems are covered.

Geometry Step by Step from the Land of the Incas - Let your interest in Incan history lead to your interest in Euclidean geometry. This site includes geometry problems, proofs, quizzes, puzzles, quotations, scientific speculation, and more.

Geodesic Club House - A wonderful site all about building geodesic domes. Learn about the strength of triangles.

Building a Bookcase - A building project is an excellent way to put geometry lessons to practical use. Build a bookshelf with a little help from Popular Mechanics.

The Golden Mean - is a mathematical expression of proportion that ancient Greek philosophers observed throughout the natural world. The simplest geometrical example of the Ratio is the golden rectangle, whose sides have unequal length but whose shape the Greeks found particularly pleasing.

High School Conic Sections, Circles - Watch for entries with stars. The stars indicate these entries are most well-liked.

Lesson on Circumference of a Circle - Learn your way around a circle at this site. Learn about circumference, radius, diameter, and pi.

The Living Witch of Agnesi - This is a gif animation of the curve known as the 'Witch of Agnesi.

Math.com Homework Help Geometry - Free math lessons and math homework help from basic math to algebra, geometry and beyond.

Math Lab - Java created virtual straightedge and compass to draw lines and circles. Lines and circles are the fundamental building blocks of the Euclidean geometry which was pioneered by Greek mathematicians over two millennia ago.

NonEuclid - NonEuclid is interactive Java software for creatng ruler and compas constructins in both the Poincare disk and the uper half-plane models of hyperbolic geometry. Hyperbolic Geometry is a geometry of Einstein's General Theory of Relativity and Curved Hyperspace.

Science U's Geometry Center - Shapes, Patterns, Symmetry! You will find these themes everywhere in the Geometry Center. Browse through an exhibit, or jump right in and start experimenting.

Postulates, Theorems, and Corollaries from Geometry - A list with links to proofs for each theorem.

Janee's Protractor - If you need help measuring angles when designing in PhotoShop add this online protractor to your drawing as its own layer. This drawing could be printed on heavy paper and used offline as well.

Quickie Math - This site contains lessons and shortcuts, geometry history, a fun games section, and a real life section. The real life section is interesting and helpful as it explains how the geometry studied can be used in real life.

Webmath Geometry - Find help with the equation of a line, plotting conic sections, graphing and plotting, and geometrical objects.

Euclid's Elements - This is a great site with all 13 books included, making this a complete geometry course.

Pythagorean Puzzle - An explanation of the Pythagorean Theorem. Named for the Greek mathematician, Pythagoras, who lived over 2,000 years ago.