Answer:
∠ACD≅∠CAB
Explanation:
According to SAS postulate if two sides and the included angle of ΔDAC are same to two sides and the included angle of ΔBCA. Then ΔDAC≅ΔBCA
But for the given figure 
∠DAC≅∠BCA and 
CA=AC (common in both triangle) 
Hence we need ∠ACD≅∠CAB to prove that ΔDAC≅ΔBCA