OER Commons
Oer Commons: Mars: Proving the Pythagorean Theorem
This lesson is intended to help you assess how well students are able to produce and evaluate geometrical proofs. PowerPoint slides are included with the lesson.
Oswego City School District
Regents Exam Prep Center: Pythagorean Theorem
Material to supplement introductory instruction on the Pythagorean Theorem. A very simple look at its use in geometry, a multiple-choice quiz through which students can test themselves and check their answers, and a teacher resource...
Cut the Knot
Cut the Knot!: Analogues and Generalization of the Pythagorean Theorem
This site discusses the theorems and other findings which are directly related to the fundamental Pythagorean theorem. Be sure to click on the link to information on Pythagorean theorem to find several proofs of the theorem.
Shodor Education Foundation
Shodor Interactivate: Squaring the Triangle
Learn about how the Pythagorean Theorem works through investigating the standard geometric proof.
Cut the Knot
Cut the Knot!: The Law of Cosines (Cosine Rule)
This site from Cut The Knot provides an overview of the law of cosines, complete with an explanation of the law and a proof of the law.