To prove that triangles \( \triangle ABC \) and \( \triangle CDA \) are congruent by the ASA Congruence Theorem, you need to demonstrate that the two angles and the included side are congruent. You have already established that \( \angle BCA \cong \angle DAC \) and \( \angle BAC \cong \angle DCA \).
The additional information you need to prove is the congruence of the sides \( AC \):
AC ≅ AC by the Reflexive Property of Congruence.
This allows you to establish the side-angle-side configuration needed for the ASA criteria, completing the proof that \( \triangle ABC \cong \triangle CDA \).