Hi Jana. 1 cubic feet of steel is a volume measurement. So is 1 sq foot area times 3/8" thickness. Let's convert first to consistent units - that's always the first step to make. 3/8 feet is 3/(8*12) feet (which simplifies to 1/32 ft), so when you multiply it by 1 sq foot, you get 1/32 cubic feet.
So your supply is 1 cubic foot of steel and your pieces are 1/32 cubic feet each. Can you see now what you need to do to solve the question?
Hope this helps,
Stephen La Rocque.