# What is the square root of 256?

May 30, 2015

$\sqrt{256} = 16$

at least that's the positive square root

$- 16$ is also a square root of 256.

${16}^{2} = {\left(- 16\right)}^{2} = 256$

By definition, the principal square root of a number is the positive square root. The term "the square root" is commonly used to refer to the principal (positive) root though there are usually two roots.

$\sqrt{{x}^{2}} = | x |$