Well, I don.t know the question or any information about the triangles, but what I do know is how to differentiate similar and congruent triangles, so i will shoot an arrow in the dark and hope I answer your question. :)
Two triangles are congruent to eachother when all three sides and angles match the same side and angle on the other triangle(s). The only difference two congruent triangles could have is rotation and location.
On the other hand, triangles are similar when their angles are equal. Similar triangles can be of different sizes, as long as they are scale to each other.
Remember that you need at least angles or sides to determine if triangles are congruent (AAS, SSA, ASA, SAS) or similar (AAA).