Answer:
x = 4√3, or approximately 6.93
Explanation:
This is a right triangle with hypotenuse 13 and side lengths x and 11. According to the Pythagorean Theorem, x^2 + 11^2 = 13^2 = 169, or
x^2 + 121 = 169, or
x^2 = 48.
x must be a positive quantity. Thus, x = +√48 = + √3·√16 = +4√3
Thus, x = 4√3, or approximately 6.93