A number that is a perfect square, is a number that is the squared of another number.
For instance, number 9 is a perfect square, becasue it is the squared of another number. Such number is 3, in fact, you have:
3 x 3 = 3² = 9
Other examples are 16, 25, 36, etc. All these numbers are perfect square: they are the squared of another numbers.
