Roots

We come across square roots and cube roots concept where we need to find a number which when multiplied by itself certain number of times gives us the original number.

$\sqrt{9}$ is 3 because 3 * 3 = 9.

relation to square in geometry

Square roots give the length of the side of a square given its area. This is exactly why it's called a square root.^

The word root here means, it will get us the fundamental measure of the geometric shape.

Similarly cube roots gives us the length of the side of a cube given its volume.

if x*x = y, then $\sqrt{y}$ is x.