Answer:
The answet is C.
Step-by-step explanation:
First, you have to find the angle of ACB using Sine Rule, sinθ = opposite/hypotenuse :





Given that line AB is parallel to line CD so ∠C = 90°. Next, you have to find the angle of ACD :

Lastly, you can find the length of CD using Cosine rule, cosθ = adjacent/hypotenuse :






12,6
10,5
Im not 100% sure if its right but thata the answer i get
17 and 3 work. 17-3=14 17+3 =20