What is the rest of the problem? I can help you!
So 7 is greater I am not smart I am just trying to answers some question
X = 12
Use the Pythagorean Theorem.
13^2 = 5^2 + x^2
169 = 25 + x^2
Subtract 25 from both sides.
144 = x^2
Take the square root.
12 = x