Answer: second option
Explanation:
You need to apply the Pythagorean theorem:

Where "a" is the hypotenuse and "b" and "c" are the legs of the right triangle.
In the figure you can observe the value the hypotenuse of the right triangle and the value of one of this leg. Then, you need to solve for the other leg from
:


Substituting values, you get that the value of "x" is:

