Answer
c=5
Work Step by Step
The Pythagorean Theorem states that for a right triangle, $a^{2} +b^{2} = c^{2}$. Thus, we plug in the values given for a, b, or c, and then we use these values to find the missing value:
$3^{2} + 4^{2} = c^{2} \\\\ 25=c^{2} \\\\ c=5$