![](http://www.scienceiq.com/Images/GrayPix.gif)
![](http://www.scienceiq.com/Images/FactsImages/square.jpg)
That number was obtained by finding the area of the four-sided shape, multiplying the length of the figure by its width. That is, by multiplying one number by another number. For a square, the length and width are equal. Finding the area of a square therefore involves multiplying a number by itself. This brings us to the general definition of the square of a number. The square of any number is that number multiplied by itself.
For example, 81 is the square of 9 because you have to multiply 9 by itself (9) to get 81. The number that gets multiplied by itself to make the square value is called the root value of that square, or the square root. This is the basis of the general definition of a square root. The square root of a number is whatever number must be multiplied by itself ('squared') to get the original number. For example, 3 is the square root of 9, because 3 must be multiplied by 3 (itself) to get 9. These relationships are true for any number.