From the diagram given, we know that all 3 angles of ∆ABC are congruent to all corresponding 3 angles of ∆DEF.
If we know just two of the angles of the two triangles given are equal to each other, it is enough information for us to prove that they are similar to each other based on the AA Similarity theorem.
The corresponding three angels of both triangles are equal, therefore, based on AA, they are similar to each other.
