Acube has a surface area of 3750 square feet find the length of one side

Surface area of cube = 6a²
6a² = 3750
⇒ a² = 3750/6 = 625
⇒ a = √625
⇒ a = 25 ft

Cube means that all sides are the same.
Surface area is to find the area of a six faces of the cube.
To find the area f each face you multiply l* w or in this case s*s or s^2
So... 6s^2 = 3750
Divide both sides by 6
s^2 = 625
Take the square root of each side
s = 25 ft.