An informative lesson contains a brief explanation of how the sum of the angles of a triangle is a line. The lesson continues with determining the missing angle in a triangle, or solving for a variable. Using the sum of the...

After reviewing characteristics of seven types of triangles, young geometers discover how to find the missing angle of a triangle. Then, they practice identifying triangles, find missing angles, and find missing side lengths of...

Stuck trying to remember the formal language of a geometric proof? Never fear, this handout has them all ready to go. The reasons are sectioned by topic so this handy guide is ready when you are to tackle those two column proofs. 

Triangles are all about threes, and practicing proving postulates is a great way to get started. The first page of the activity provides a brief introduction of the different properties and postulates. The remaining pages contain...

Explains the basic concept of isosceles triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.