Given:
AB = 6, AD = x, CD = 16, and CB = 12.
To find:
The value of x.
Solution:
Consider the below figure attached with this question.
In the figure BD is the angle bisector. So, using angle bisector theorem, BD divides the opposite sides in the ratio of other two sides.



Multiply both sides by 16.


Therefore, the value of x is 8.