Answer:
∠ ACB = 39°
Explanation:
the exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
∠ BDA is an exterior angle of Δ ACD , then
∠ CAD + ∠ ACB = ∠ ACD , that is
29° + ∠ ACB = 68° ( subtract 29° from both sides )
∠ ACB = 39°