What is the square root of 9?

The square root of 9 is 3. This is because 3 multiplied by itself (3 x 3 = 9) equals 9. It's also worth noting that -3 is also a square root of 9, since (-3) x (-3) = 9. However, when we talk about the square root (often denoted as √9), we typically refer to the principal square root, which is the positive one (3).