Which pair of angles must be congruent?

Since I am not sure which shapes you are using I cannot fully answer this question, but to make two or more angles congruent, they must contain the same angle degree.

For example, if triangles GHI and FJK are congruent, angles HIG and JKF will be congruent and so will angles IGH and KFJ along with angles GHI and FJK.

Hope this helped :)

The answer would be 315 because you need to subtract