Other
The Mathematical Elements of Euclid
An extensive discussion of the Elements, which contains all the geometrical knowledge available in the Hellenistic period.
CK-12 Foundation
Ck 12: Analysis: Induction and Inequalities
[Free Registration/Login may be required to access all resource tools.] The transitive property of inequality and induction with inequalities. Students examine guided notes, review guided practice, watch instructional videos and attempt...
Math Planet
Math Planet: Geometry: Proofs Using Algebra
Examples and a video lesson help to explain proofs and logic. [1:57]
Rice University
Rice University: Cynthia Lanius: History of Geometry
Different cultures' contributions to Geometry are discussed.
CK-12 Foundation
Ck 12: Interactive Geometry: 4.1 Theorems and Proofs
Understand theorems and proofs as they relate to geometry.
ClassFlow
Class Flow: Congruence in Triangles
[Free Registration/Login Required] This lesson helps teach congrence in triangles. Includes practice with postulates, theorems, and logical reasoning.
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.