Khan Academy on a Stick
Similarity

Similar Triangle Basics
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Introduction to what it means for triangles to be similar

Similarity Postulates
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Thinking about what we need to know whether two triangles are similar

Similar Triangle Example Problems
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Multiple examples looking for similarity of triangles

Similarity Example Problems
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Two example problems involving similarity

Similarity example where same side plays different roles
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The same side not corresponding to itself in two similar triangles

Challenging Similarity Problem
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Interesting similarity problem where we don't have a lot of information to work with

Finding Area Using Similarity and Congruence
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Example of using similarity and congruence to find the area of a triangle
Triangle similarity
This tutorial explains a similar (but not congruent) idea to congruency (if that last sentence made sense, you might not need this tutorial). Seriously, we'll take a rigorous look at similarity and think of some reasonable postulates for it. We'll then use these to prove some results and solve some problems. The fun must not stop!

Similar triangles
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Introduction to similar triangles

Similar triangles (part 2)
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More on similar triangles
Old school similarity
These videos may look similar (punintended) to videos in another playlist but they are older, rougher and arguably more charming. These are some of the original videos that Sal made on similarity. They are less formal than those in the "other" similarity tutorial, but, who knows, you might like them more.