To find the value of x, we need to use Pythagorean Theorum.
The equation for Pythagorean Theorum is a^2 + b^2 = c^2.
C^2 is our hypotenuse, or the side that's across from the right angle.
13 is our hypotenuse, and 12 is b.
Since our numbers are not squared, let's square them.
13 x 13 = 169
12 x 12 = 144.
Our equation now is a^2 + 144 = 169
To find a^2, we need to subtract b^2 from c^2.
Subtract 144 from 169.
169 - 144 = 25.
a^2 = 25
Square root both sides.
a = 5.
x = 5.
I hope this helps!