How to calculate the side length of a square with an area of 20 square meters Please let me know the formula, thank you!

How to calculate the side length of a square with an area of 20 square meters Please let me know the formula, thank you!

Because the sides of a square are equal, the area is equal to the length of the side multiplied by the length of the side
Set the side length to R
R*R=20
Side length r = √ 20 (read as root 20)
I don't know if you can open the root, √ 20 = 2 * √ 5 ≈ 2 * 2.236 ≈ 4.472