EXPLANATION
Given the right triangle, we can find the length of the third side by applying the Pythagorean Theorem:
Let's call x to the unknown side
[tex]12^2+x^2=20^2[/tex]
Subtracting 12^2 to both sides:
[tex]x^2=20^2-12^2[/tex]
Solving the powers:
[tex]x^2=400-144=256[/tex]
Applying the square root to both sides:
[tex]x=\sqrt[]{256}[/tex]
Simplifying:
[tex]x=16[/tex]
The answer is x=16
