The incenter of a triangle deals with the angle bisectors of a triangle. This tutorial shows you how to find the incenter of a triangle by first finding the angle bisectors.

Perpendicular lines have a special property. The angles formed by perpendicular lines will always be the same. Check out this tutorial to learn about perpendicular lines and see a cool trick involving these special lines!

If two figures have the same size and shape, then they are congruent. The term congruent is often used to describe figures like this. In this tutorial, take a look at the term congruent!