what is the value of $sqrt{81}$? enter the answer in the box.

Explanation:

Step1: Recall square - root definition

The square - root of a number $x$, denoted as $\sqrt{x}$, is a value $y$ such that $y\times y=x$. We need to find a number $y$ where $y^2 = 81$.

Step2: Identify the number

We know that $9\times9 = 81$ and $(- 9)\times(-9)=81$. In the case of the principal square - root (denoted by $\sqrt{x}$ where $x\geq0$), we take the non - negative value. So $\sqrt{81}=9$.

Answer:

9