Geometric Proofs

Looking to challenge your students that have mastered basic triangle congruence proofs? A collection of proofs employ previously learned definitions, theorems, and properties. Pupils draw on their past experiences with proofs to...

Can they put it all together? Ninth graders apply what they know about proofs and triangle congruence to complete these proofs. These proofs go beyond the basic triangle congruence proofs and use various properties, theorems, and...

This amazingly extensive unit covers a wealth of geometric ground, ranging from constructions to angle properties, triangle theorems, rigid transformations, and fundamentals of formal proofs.  Each of the almost-forty lessons is broken...

Is this enough to show the two triangles are congruent? Small groups work through different combinations of constructing triangles from congruent parts to determine which combinations create only congruent triangles. Participants use the...

Geometric figures are perfect to use for proofs. Scholars prove conjectures about whether given points lie on a triangle and about midpoints. They use a provided dialogue among fictional learners to frame their responses.

It's time to prove one's knowledge of triangle congruence proofs. Scholars watch a video to review triangle classifications and how to use properties of triangles to set up and solve equations for missing values. They also review the...

The proof is in the review. Individuals watch a short review of the content from the unit to prepare for the unit exam. The review covers inductive reasoning, conditional and related statements, and two-column algebraic and geometric...

Why is it a two-column proof? A video introduces the class to the concept of a two-column proof and how to set one up. The segment of a playlist on basic geometry highlights the types of reasons that can be in a proof.

Looking at numerous examples of triangles, each with different properties, geometers develop their understanding of congruency. They use the notation of a counter-example to disprove certain conjectures and prove geometric theorems and...

[Free Registration/Login may be required to access all resource tools.] This study guide reviews proofs: algebraic proof, properties of congruence, and geometric proofs (two-column).