You can use the Pythagoras theorem to get the value of x.
The value of x is given by
Option C: x = 6.2
<h3>What is Pythagoras theorem?</h3>
The Pythagoras theorem:
If ABC is a triangle with AC as the hypotenuse and angle B with 90 degrees then we have:

<h3>Using the above theorem to find the value of x for the given figure</h3>
Refer to the figure attached below.
The triangle BAD is right angled triangle (one angle is 90 degrees).
The length of CD is 13 - x units.
Thus, we have:

For triangle ACD, we have:

For triangle ACB, we have;

Thus,
The value of x is given by
Option C: x = 6.2
Learn more about Pythagoras theorem here:
brainly.com/question/12790596