Final answer:
To find the value of x, we can use the fact that the sum of the lengths of the opposite sides of a parallelogram is equal. In this case, AD = CB and AB = CD. Therefore, x + 12 = 6 + 16. Solving this equation, we find that x = 10.
Step-by-step explanation:
To find the value of x, we can use the fact that the sum of the lengths of the opposite sides of a parallelogram is equal. In this case, AD = CB and AB = CD. Therefore, x + 12 = 6 + 16. Solving this equation, we find that x = 10. So the value of x is not given in the options provided.