i dont know how to do this one

Answer:
[tex]2\sqrt{34}[/tex]
Step-by-step explanation:
We can add a line to create a triangle and a rectangle. The triangle will have side lengths 10 and 6. Furthermore, it will be a right triangle, meaning we can apply the Pythagorean Theorem to find x, the hypotenuse.
[tex]6^2 + 10^2 = x^2\\x = \sqrt{6^2 + 10^2}\\ = \sqrt{136} \\= 2\sqrt34}[/tex]
hope this helped! :)