Pythagorean Theorem
a^2+b^2=c^2
12^2+x^2=20^2
144+x^2=400
x^2=256
[tex]x = \sqrt{256} = 16[/tex]
12²+x²=20²
144+x²=400
400-144=256 . 144-144=0
x²=256
=16
