Answer:
Okay, there are many ways to find if a triangle is congruent.
Let's start with some different terminology.
For the sake of simplicity let us say that S stands for when a side is congruent for both triangles and A stands for when an angle (<) is congruent between both the triangles as well.
So, you need to memorize some rules. If you find that 2 triangles are congruent in the sense of; SSS, SAS, AAS, SAA, and ASA. One thing to remember is that Angle Side Side isn't congruent and is called <em>Donkey Theorem</em>. This theorem only works for right triangles.
One way to know if your triangle isn't congruent is if you can find a part of the triangle that is different.
I know that wasn't the best explanation but I hope it helped anyhow. :)
