Learn what it means for two figures to be congruent, and how to determine whether two figures are congruent or not. Use this immensely important concept to prove various geometric theorems about triangles and parallelograms.

Two figures are congruent if you can go from one to another through some combination of translations, reflections and rotations. In this tutorial, we'll really internalize this by working through the actual transformations.

Now that we know how to show that two triangles are congruent, let's put that to use by proving some theorems about triangles.

Triangle congruence is not only useful when working with triangles, it's also useful with any other kind of polygon! Prove a few theorems about the properties of parallelograms using triangle congruence.