What is the square root of 81?

The square root of a number is a value that, when multiplied by itself, yields that number. In this case, you're looking for a number that would result in 81 when squared. The calculation is straightforward: 9 multiplied by 9 equals 81. Therefore, the square root of 81 is indeed 9. This foundational concept is crucial in mathematics, as it is often used in various applications, including geometry, algebra, and beyond. Understanding how to identify square roots helps in solving equations and in comprehending the relationships between numbers.