The appropriate statement to place at the end of the proof is:
Finally, ∠A≅∠C by the Base Angles Theorem.
or
Finally, angle upper A congruent to angle upper C by the Base Angles Theorem.
This conclusion follows from the fact that in an isosceles triangle, the angles opposite the equal sides are congruent. Hence, since we have established that triangles ABD and CBD are congruent, it implies that the angles at A and C are also congruent.