If you want to find the decimal value of a square root, you can use the 2 closest perfect squares to them.
Example
Approximate the value of sqrt20
Pick the 2 closest perfect squares, one before and one after 20:
16 and 25.
So, the square root of 20 has to be between 4 and 5.
Since 20 is closer to 16 than it is to 25,
We can estimate the decimal value of sqrt20 to be around 4.4
