How can you tell if a decimal is a perfect square?

Answer 1

Well, honey, if you wanna know if a decimal is a perfect square, all you gotta do is take the square root of that bad boy. If the square root gives you a whole number, then ding ding ding, you've got yourself a perfect square. If it spits out a messy decimal, then sorry, that number ain't playing nice with the squares.

Answer 2

The most obvious answer here is to simply take it's square root, and see if the answer is an integer. If it is, then your number is a perfect square.

If you don't know it's square root offhand and don't have a calculator handy, you could do it by adding up a series of odd numbers, and seeing if they reach a sum that is equal to the original number. If they do, then you have a perfect square. Otherwise, you don't.

For example, is 36 a perfect square? Let's find out:

0 + 1 = 1

1 + 3 = 4

4 + 5 = 9

9 + 7 = 16

16 + 9 = 25

25 + 11 = 36

Since we hit 36 with our addition, we know that 36 is indeed a perfect square.