Sometimes you will need to use a more formal approach to demonstrate that two triangles are congruent. In this topic, you will explore how to use a formal proof to prove that two triangles are congruent. A two-column formal proof is a well-organized way of stating what you know and how you know it. You will rely on the five triangle congruence criteria to help you prove that two triangles are congruent.

Essential Question

• How can you use a formal proof to prove two triangles are congruent?

 

Warm-Up

In this non-graded interactivity, test your knowledge about the theorems and postulates that can be used to prove triangles are congruent. Click the player button to get started.