Given:
Volume of a cubed room = 8000 cubic ft
Cost of floor hardwood = $10 per square foot
To find:
The total cost of floor hardwood.
Solution:
Let the each side of cubed room be x ft.
Volume of a cube is cube of its side.
Volume of a cubed room is 8000 cubic ft. So,

Taking cube root on both sides.

So, length of each of room is 20 ft.
Area of base = length × breadth
So, area of base of room is

It means, 400 sq ft hardwood is required for the floor.
Cost of floor hardwood is $10 per square foot. So, total cost of hardwood floor is

The hardwood floors will cost $4000.