# How do you find the square root of 25?

Jan 25, 2017

$\sqrt{25} = 5$

#### Explanation:

A square root of a number $n$ is a number $r$ such that ${r}^{2} = n$

In the case of $25$ we find that ${5}^{2} = 25$, so $5$ is a square root of $25$.

Note that $- 5$ is also a square root of $25$, in that:

${\left(- 5\right)}^{2} = \left(- 5\right) \times \left(- 5\right) = 25$

"The" square root usually refers to the positive square root, sometimes known as the principal square root.

In symbols, we write:

$\sqrt{25} = 5$

Note that $\sqrt{\ldots}$ refers to the principal square root. If we want to say that either square root can be used, we could write $\pm \sqrt{\ldots}$