If x is the side of the square, the area of a square is equal to x².
As a function of x, area is expressed as:
f(x) = x² (or simply put y=x²)
In this function, x is the independent variable. It means that when x (domain) changes, y (range) changes.
If x = 4 meters, then:
f(4) = (4 m)²
f(4) = 16 m²
If x = 7 meters, then:
f(7) = (7 m)²
f(7) = 49 m²
It means that the area of a square is dependent on the measure of its side.