We will have the following:
*First: SInce we have 36 boxes and we can stack a maximum of 3 boxes, we will have to determine the base area of one third of the total number of boxes, that is:
So, we will have to determine the base area for 12 boxes.
*Second: We determine the base area for one box:
So, each box will occupy a base area of 21 square feet.
*Third: We find the base area for the 12 boxes:
So, the floor space needed to store all boxes is at minimum 252 square feet.