What is the square root of 64?

The square root of a number is a value that, when multiplied by itself, gives the original number. In this case, 64 can be expressed as 8 multiplied by 8 (8 x 8 = 64). Thus, the square root of 64 is 8. This is why selecting 8 is correct, as it fulfills the definition of a square root accurately.

The other numbers listed do not satisfy the equation for the square root of 64, as none of them, when multiplied by themselves, equal 64.