Hey!
Hope this helps...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We know the following things:
Line AB is congruent with Line AD
Line CA is congruent with Line EA
Triangle ABC must be congruent with Triangle ADE
Therefore, because we know that these Triangles MUST be congruent with each other, we know that Line CB has to be congruent with Line DE...
As this would be the only way for these triangles to be congruent with each other...