Equations and geometry

Do the angles in a triangle always add up to the same thing? Would I ask it if they didn't? What do we know about the angles of a triangle if two of the sides are congruent (an isosceles triangle) or all three are congruent (an equilateral)? This tutorial is the place to find out.

Named after the Greek philosopher who lived nearly 2600 years ago, the Pythagorean theorem is as good as math theorems get (Pythagoras also started a religious movement). It's simple. It's beautiful. It's powerful.

In this tutorial, we will use what we learned about similarity of polygons in the specific case of triangles. We will come up with specific conditions for triangles to be similar, and use them to determine whether two triangles are similar.
Practice test
Test yourself with these 10 questions