# Square Roots

Square roots are numbers that, when multiplied by itself, will give the original nonnegative numbers.

Example: 6 times 6 = 36 and −6 times −6 = 36.

1. Find the square roots of 121.
A.
B.

Question 1 of 2

2. Find the square roots of 100.
A.
B.
C.

Question 2 of 2

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Video Transcript.

Recall this:
x2 = x times x, or x・x
This is the “Square of a Number” or the number squared.

The number x2 is called the square of the number x.
So, for example:

92 = 9・9 which equals 81. So, the number of 81 is the square of our number 9.
– 42 = – 4・- 4 which equals 16. So, the number of 16 is the square of our number −4.

Below the video, we’ve put a “List of Squares” of all whole numbers from 0 (zero) through 25. Please check that out.

Square Roots
By the time you’ve mastered the concept of squaring whole numbers, you are all set for the inverse process of squaring: determining square roots of whole numbers.

Above, we’ve seen that 92 equals 81.
We named that number 81 a square of our number 9.

We name that number 9, conversely, the square root of our number 81.

We’ve also seen that – 42 equals 16. We named the number of 16 the square of our number −4.
We name −4, conversely, the square root of our number 16.

Square Roots

So when a2 = b, we call the number “a” a square root of the number “b”.
For example, let’s find the square roots of 49.

Well, to find a square root of the number 49, we need to think of a number in a way that a2 = 49. Now, two (2) numbers come to mind:

72 equals 49. So the number 7 is a square root of our number 49.
-72 equals 49. So the number -7 is also a square root of our number 49.

So you notice that our number 49 has two (20) square roots, a positive one and a negative one.

## List of Squares It may be a good idea is you would memorize this list.