To discern whether or not triangles are congruent, you should try using the Pythagorean Theorem (a²+b²=c², where a and b are legs, and c is the hypotenuse) to make sure that all the sides have an equal length. Then find the area just to verify that they are congruent (A=1/2bh).
We can use these to find whether two triangles using SAS (side angle side) postulate. If the lengths of two sides of a triangle and the angle of their connecting angle (ideally named) match up with the measurements of a side, angle, and side of another triangle, they are congruent.
