Question

what is the unknown side of the triangle?

Answer 1

use the Pythagorean Theorem. $a^{2}$ + $b^{2}$ = $c^{2}$

so it would, $12^{2}$ + $16^{2}$ = $c^{2}$

so what you do now is simplify $12^{2} + 16^{2}$, which will equal 400.

so now you have $c^{2} =400$, so then you square root 400 to get rid of the squared. 

$\sqrt{ c^{2} } = \sqrt{400}$


$\sqrt{400} = 20$

so your unknown side is 20 :P