What is the square root of 81?

The square root of 81 is a number that, when multiplied by itself, equals 81. The <a href="https://www.wikiwhat.page/kavramlar/principal%20square%20root">principal square root</a> of 81 is 9, because 9 * 9 = 81. While -9 also satisfies the condition (-9 * -9 = 81), the principal square root is the positive root. Therefore, √81 = 9. This concept falls under the broader topic of <a href="https://www.wikiwhat.page/kavramlar/radicals">radicals</a> in mathematics.