Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Two Column Proofs

For Students 9th - 10th Standards
A response to an inquiry of how to prove a two column geometric proof problem at the Math Forum. This site gives a description of what a makes a proof and an example of a two column proof.
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Building Two Column Proofs

For Students 9th - 10th Standards
Use this site to find details of how to construct a two column proof. Dr. Math responds to a question posed by a student and details the reasons for the order of steps and shows two different ways to do the same proof.
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Faq About Proofs

For Students 9th - 10th Standards
This site provides links to questions sent in to Dr. Math about proofs. Topics covered include what proofs are, how to understand them, and how to build them, and much more. Be sure to click on the links which you believe may be helpful.
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: The Value of Two Column Proofs

For Students 9th - 10th Standards
This site explains why we prove things. The explanation gives real world scenarios and an everyday example of why we should learn how to prove things.
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Order of a Proof

For Students 9th - 10th Standards
The site gives a diagram of steps to a proof. Dr. Math explains why the step order of a proof is important.