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### Course: High school geometry > Unit 4

Lesson 2: Introduction to triangle similarity- Intro to triangle similarity
- Triangle similarity postulates/criteria
- Angle-angle triangle similarity criterion
- Determine similar triangles: Angles
- Determine similar triangles: SSS
- Determining similar triangles
- Prove triangle similarity
- Triangle similarity review

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# Triangle similarity review

Review the triangle similarity criteria and use them to determine similar triangles.

## What are the triangle similarity criteria?

AA | Two pairs of corresponding angles are equal | |

SSS | Three pairs of corresponding sides are proportional | |

SAS | Two pairs of corresponding sides are proportional and the corresponding angles between them are equal |

*Want to learn more about the triangle similarity criteria? Check out this video.*

## Check your understanding

*Want to practice more problems like this? Check out this exercise for the AA criterion and this exercise for the SSS criterion.*

## Want to join the conversation?

- i dont get most of this stuff(27 votes)
- Try to practice upon it and you might get it, or just use khan academy's practice a lot. Hope it helps(22 votes)

- How can you tell the difference between SAS and SSA? (Assume you had a problem and had to chose if it was sim. because of SAS or SSA, how would you figure it out?)(12 votes)
- SAS means that the angle is in between the two sides in question. SSA means the angle is not in between.(20 votes)

- The videos im watching is not adding up to the working you guys are giving me. Im so lost.(12 votes)
- Yo, man. This is how we do da thing. Firstly, if the triangles have 2+ matching corresponding angles, then it is similar. If it has side lengths that can be divided by a number, say X, and then match the side lengths of your other triangle, then it is similar. If it has 2 matching corresponding(see last sentence) sides, and the angle between these is the same, then it is similar. -Beauregard42. If this helps you, your welcome.(8 votes)
- An equation is a statement with an equals sign.

So*3 + 5 = 8*and*5x + 12 = (x / 4) + 3*are both equations,

but*24 * 9*and*3y ≥ x - 8*are not equations.(12 votes)

- What other triangle similarity criteria can be used?(3 votes)
- I believe AA, SAS, and SSS are the only triangle similarity theorems(5 votes)

- i don't get it sometimes(3 votes)
- Is there anything I can do to help you?(2 votes)

- I thought I thought I would need a calculator for quiz 1,

But I got a 100% Without even trying.

*And I never did this before!*(3 votes) - gelp im in 8 doing this while other people are doing calculus rn :sob:(3 votes)
- why does this make sense(6 votes)
- Because it just does.(0 votes)