CK-12 Foundation
Ck 12: Interactive Geometry: 4.8 Applications of Quadrilateral Theorems
Explore quadrilateral properties and threorems.
CK-12 Foundation
Ck 12: Interactive Geometry: 4.6 Applications of Triangle Theorems
Explore applications of triangle theorems.
CK-12 Foundation
Ck 12: Interactive Geometry: 4.3 Applications of Line and Angle Theorems
Learn the four categories of theorems that have to do with lines and angles.
CK-12 Foundation
Ck 12: Interactive Geometry: 4.4 Theorems About Triangles
Discover some theorems about triangles.
CK-12 Foundation
Ck 12: Interactive Geometry: 4.1 Theorems and Proofs
Understand theorems and proofs as they relate to geometry.
CK-12 Foundation
Ck 12: Interactive Geometry: 1.7 the Pythagorean Theorem
Explore and discover the Pythagorean theorem.
National Council of Teachers of Mathematics
Nctm: Illuminations: Proof Without Words: Completing the Square
Use this interactive geometric proof to complete the square using geometry.
Geometry Help
Geometry Help: Tangent Lines
Explains the basic concept of congruent triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
Dartmouth College
Dartmouth College: The Different Styles of Euclid and Copernicus
A history of the differences between Euclid's and Copernicus's methods of proving geometric ideas.
National Council of Teachers of Mathematics
The Math Forum: Analytic Geometry Formulas, Hyperbolas
At this site from the Math Forum, a brief overview on calculating various measures of segments, like the transverse and conjugate axes and the distance between foci, is given. Additionally, equations of hyperbolas in general, standard,...
Wolfram Research
Wolfram Mathworld: Elliptic Geometry
MathWorld offers a brief definition of elliptic geometry and including a brief discussion of its relationship to Euclidean geometry, with links to other related definitions.
National Council of Teachers of Mathematics
The Math Forum: Geometry Turned On
This Math Forum site contains many mathematical and geometric explanations and proofs of many different topics that have been done using a geometry software called Geometer's Sketchpad. The explanations are very detailed and clear;...
National Council of Teachers of Mathematics
The Math Forum: Analytic Geometry Formulas
This site from The Math Forum defines and explains, with examples, analytic geometry. Content includes a focus on one, two, and three dimension analytic geometry. Links are also provided for additional information.
Wolfram Research
Wolfram Math World: Coplanar
This MathWorld site gives the conditions for an object to be coplanar and a good definition of this term. Gives links to related pages.
Maths Challenge
Maths challenge.net: Cables
This is a proof problem, considered a "three star" geometry problem requiring knowledge of proofs and properties of circles to solve this problem with cables in duct problem.
Maths Challenge
Maths challenge.net: Radical Axis
This is a "three star" geometry problem requiring knowledge of proofs and properties of circles. Students will use the given definition of radical axis and prior knowledges to prove a way to find a radical axis.
ClassFlow
Class Flow: Algebra, Geometry Conic Review
[Free Registration/Login Required] Flipchart helps student to interpret algebraic equations and inequalities, geometry (cones, spheres, parabolas, etc.) and describes geometric relationships algebraically.
ClassFlow
Class Flow: Graph of an Equation
[Free Registration/Login Required] In 1637, Rene Descartes revolutionized the study of mathematics by joining its two major fields, algebra and geometry. With Descartes's coordinate plane, geometric concepts could be formulated...
Wolfram Research
Wolfram Math World: Spherical Geometry
Site provides a brief explanation of the discipline of Spherical Geometry along with many links to spherical geometry topics.
University of British Columbia
University of British Columbia: Proof of the Pythagorean Theorem
A geometric model that proves the Pythagorean Theorem in a step-by-step diagram that students can advance at their own pace. Requires Java.
Wolfram Research
Wolfram Math World: Postulate
This MathWorld site defines postulates, and explains how and where they are used in mathematics. The site has numerous links to related terms.
Wolfram Research
Wolfram Mathworld: Theorem
This simple MathWorld site defines theorems and briefly explains how a theorem is produced.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Triangle Altitudes
Here at the Math Forum, Dr. Math proves the concurrency of the altitudes of a triangle. Links are provided for associated topics.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Proving the Pythagorean Theorem
This Ask Dr. Math site explains how to prove the Pythagorean Theorem. Dr. Math gives three variations for proving the theorem.