# Square roots review

Review square roots, and try some practice problems.

### Square roots

The square root of a number is the factor that we can multiply by itself to get that number.
The symbol for square root is $\sqrt{ }$ .
Finding the square root of a number is the opposite of squaring a number.
Eksempel:
$\blueD4 \times \blueD4$ or $\blueD4^2$ $= \greenD{16}$
So $\sqrt{\greenD{16}} = \blueD4$
If the square root is a whole number, it is called a perfect square! In this example, $\greenD{16}$ is a perfect square because its square root is a whole number.

## Finding square roots

If we can't figure out what factor multiplied by itself will result in the given number, we can make a factor tree.
Eksempel:
$\Large{\sqrt{36} = \text{?}}$
Here is the factor tree for $36$:
So the prime factorization of $36$ is $2\times 2\times 3\times 3$.
Vi ser etter $\sqrt{36}$, så vi ønsker å dele opp primtallsfaktorene i to like grupper.
Notice that we can rearrange the factors like so:
$36 = 2 \times 2 \times 3 \times 3 = \left(2\times 3\right) \times \left(2 \times 3\right)$
$\left(2\times 3\right)^2 = 6^2 = 36$.
So, $\sqrt{36}$ is $6$.

## Practice

Want to try more problems like this? Check out this exercise: Finding square roots
Or this challenge exercise: Equations with square and cube roots