Answer:
ASA Congruence Theorem
Step-by-step explanation:
Already,it has been stated and proved that two angles (<ABC and <CAB) and an included side (AB) in ∆ABC are congruent to corresponding two angles (<ABD and <DAB) and an included side (AB) in ∆ABD.
Therefore, based on the ASA Congruence Theorem, ∆ABC is congruent to ∆ABD.
The missing reason is "ASA Congruence Theorem"
