Similarity

This course is a part of Mathematics II, a 14-course Topic series from Khan Academy.

Learn what it means for two figures to be similar, and how to determine whether two figures are similar or not. Use this concept to prove geometric theorems and solve some problems with polygons.

This course contains 6 segments:

Definitions of similarity

In this tutorial, you will learn how we determine whether two figures are similar.

Introduction to triangle similarity

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.

Solving similar triangles

Learn how to find missing measures of triangles using the fact that they are similar to other triangles.

Angle bisector theorem

Learn about the angle bisector theorem, which makes a clever use of triangle similarity in order to find a special proportion that holds for angle bisectors of triangles.

Solving problems with similar & congruent triangles

You already saw how we can use similarity and congruence to find missing measures in triangles. Let's do the same now to solve more kinds of polygons, and more challenging problems!

Solving modeling problems with similar & congruent triangles

Now that you are an expert with solving geometry problems using congruence and similarity, you are ready to solve some real-world problems!