so if you look at the angle they both have a 90 and the larger triangle is just flipped a different way. because triangles must add up to 180, you have your 90 degree angle on both and the larger one has one degree of 50 meaning its other angle must be 40 in order to add up to 180 and the smaller triangle is the opposite as it has a 40 and 90 degree angle meaning the other must be 50 therefore have Angle Angle similarity
