Verified answer

∠A = 180 -(∠B +∠C) or

∠A = 180 - 3*(∠C)-------------------------------- 1.

But its should be given that AD = DC (and not AB = BC as given) So as AD is bisector of A

(∠A )/2 = ∠C ---------------------------- 2 or multiplying by 3 we get

(3/2)∠A = 3∠C -------------------------- 3

Adding 1 and 3, we get

(5/2)∠A = 180 or

∠A or ∠BAC = 360/5 = 72

hence proved.