Answer: SSS postulate and CPCTC will be used to prove ∠ ACD ≅ ∠ DBA.
Step-by-step explanation:
By joining the points A, C with points D and B respectively,
We get a quadrilateral ABCD in which AB ≅ CA ( given)
And, diagonal AC ≅ diagonal BD
In triangles ABD and ADC,
AB ≅ CA
AC ≅ BD
AD ≅ AD ( reflexive )
Thus, by SSS postulate,
Δ ABD ≅ Δ ADC
Thus, By CPCTC,
∠ ACD ≅ ∠ DBA