Video Transcript

Hi, I'm Charlie Kasov. I'm a math teacher and today we're going to learn what conditions are necessary to prove that two Isosceles triangles are congruent. Now for triangles to be congruent all the sides have to be equal. So the thing about two Isosceles triangles is let's say we have this where this is 5 and this is 5 but this is 6 and then we have again 5, 5 and 6, well these are Isosceles because two of the sides are equal and two of the angles are equal, this angle and this angle and then this angle and this angle. These are definitely congruent because the sides are. Now if we had an Isosceles triangle like this, where it was 6 and 6 but then here it's 4 and 4, but all the angles were the same like this was 45 and 45 and this was 45 and 45, well these are not congruent. They're similar because the angles are all the same which means that they're proportional but they're not congruent because the sides are not the same. So again, in order for Isosceles triangles to be congruent, the sides have to all be the same and that really goes for any triangle. I'm Charlie Kasov, and you just learned how to determine if two Isosceles triangles are congruent. Thanks a lot.