Since AC>AB, the angles opposite to the sides will also have the same relation.
=>∠B>∠C
From the figure, we see that △ABD and △ACD have angles ∠BAD and ∠CAD equal as AD is the angle bisector of ∠A
We know that sum of angles in a triangle =180o
So, in the two triangles, △ABD and △ACD
if ∠BAD=∠CAD
∠B>∠C
=>∠ADB<∠ADC as the sum of all angles should be =180o
Hence, ∠ADC is greater than ∠ADB