**The square root of 225 is 15.** The square root of a number is the value that can be multiplied by itself to equal the original number. Fifteen multiplied by 15 equals 225, thus making 15 the square root of 225.

A perfect square is achieved by taking a positive integer and multiply it by itself. Examples of perfect squares are 1, 4, 9, 16, 25 and 225.

Every mathematical operation has an inverse operation. The inverse operation of finding a square root is squaring a number. Squaring a number is simply multiplying that number by itself. For example, to square 15 means to multiply 15 by 15, which equals 225.