This video introduces all the nitty gritty of congruent shapes like: what are they, what are they not, does size matter, does orientation matter, mirroring, etc. Basic stuff but good stuff.
Definition of Corresponding Parts
This video introduces the concept of corresponding parts: what are they and what are they good for. This will end up being a really important concept in triangle proofs when we get into "CPCTC." What does that stand for? You don't want to know (but could find out with a quick search in the search bar above).
If you do not have an account, you should get one, because it is awesome! You can save a playlist for each test or each chapter, and save your "greatest hits" into a "watch right before the final" list (not that we recommend cramming, but when in Rome...)