Square root

Property The square root of a number $x$, written as $\sqrt{x}$, is the number that, when squared, equals $x$. It is the inverse of squaring, so if $s^2 = A$, then $s = \sqrt{A}$.

Examples Since $4^2 = 16$, the square root of 16 is 4, which is written as $\sqrt{16} = 4$. A square sandbox has an area of 169 square feet. The side length is $\sqrt{169} = 17$ feet. The solution to the equation $b = \sqrt{4}$ is $b=2$.

Explanation Finding a square root is like being a geometry detective! If you know the total area of a square room, the square root tells you the exact length of one of its sides. It’s the ultimate “undo” button for the squaring operation you just learned.