5) Choose which postulate proves the triangles congruent.

ΔBAC and ΔDAC are the congruent triangles by ASA postulate of the congruence of two triangles.
In ΔBAC and ΔDAC,
Given properties are,
By using these properties,
∠BAD ≅ ∠DAC (Given)
∠BCA ≅ ∠DCB (Given)
AC ≅ AC (Reflexive property)
ΔBAC ≅ ΔDAC (ASA postulate of congruence of two triangles)
Therefore, ΔBAC and ΔDAC will be congruent by ASA postulate for the congruence of two triangles.
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