What are Square Roots?
Definition of a square root: The opposite of squaring a number. For example, finding the square root of 81 is the same as asking, "what number, when squared, is equal to 81?"
Of course, if you know that 9 x 9 = 81, you will know that the square root of 81 is 9 (92 = 81). However, what you might not realize is that -9 is also a square root of 81, because -9 x -9 also equals 81.
In other words, all numbers greater than zero (zero can never be negative or positive) have two square roots -- one positive and one negative. This is why when using an online square root calculator, the result will always be preceded by a ± sign.
As for negative numbers, since a negative times a negative always yields a positive number, negative numbers cannot have a real value square root.
What Are Perfect Squares?
When a number has a square root that is a whole number, that number is said to be a perfect square. For example, since √4 has a square root of 2, 4 is said to be a perfect square. Here is a list of the perfect squares up to 225:
If you are still having a hard time understanding square roots, please let me know in the feedback form located beneath the calculator, and I will try to improve my explanations on this page.
Can I get a "root! root!"? :-)