Respuesta :

The volume = a x b x c 
or base x height x top
therefore if the base of the box is 5 square feet then so is the top of the box 

5 x 11.5 x 5 = the volume
volume of a regular prism=height times area of base
area of base=5
height=1 and 1/2

volume=5 times 1 and 1/2
volume=5+5/2
volume=15/2 aka 7.5 ft^3