Khan Academy on a Stick
Similarity
Testing similarity through transformations
Quadrilateral similarity by showing congruent anglesSimilarity and transformations
Two figures are similar if you can get from one to another through some combinations of translations, reflections, rotations AND DILATIONS (so you can scale up and down). This tutorial helps give us an intuition for this.
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Similar triangle basics
Introduction to what it means for triangles to be similar
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Similarity postulates
Thinking about what we need to know to determine whether two triangles are similar
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Similar triangle example problems
Multiple examples looking for similarity of triangles
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Similarity example problems
Two example problems involving similarity
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Similarity example where same side plays different roles
The same side not corresponding to itself in two similar triangles
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!
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Finding area using similarity and congruence
Example of using similarity and congruence to find the area of a triangle
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Golden ratio and Rembrandt's self portrait
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Triangle similarity in pool
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Golden ratio to find radius of moon
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Challenging similarity problem
Interesting similarity problem where we don't have a lot of information to work with
Solving problems with similar and congruent triangles
We spend a lot of time in geometry proving that triangles are congruent or similar. We now apply this ability to some really interesting problems (seriously, these are fun)!
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Similar triangles
Introduction to similar triangles
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Similar triangles (part 2)
More on similar triangles
Old school similarity
These videos may look similar (pun-intended) 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.