Question 866566
The connection with pyramids and rectangular prisms (ie "boxes") is this



(Volume of Pyramid) = (1/3)*(Volume of Rectangular Prism)



Note: This equation is true if they both have the same base area and same height.



The box or rectangular prism has a volume of V = L*W*H = 5*5*9 = 225 cubic feet.



So the pyramid has a volume of 1/3 of that, equal to (1/3)*225 = 75 cubic feet.



The amount of empty space is equal to the difference of the two: 225-75 = 150



The volume of empty space is <font color="red">150 cubic feet</font>