what is the value of $sqrt{81}$?

Explanation:

Step1: Recall square - root definition

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

Step2: Find 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