to find the valume of a rectangular prism we need to multipy the height the width and the length of our prism. but for this to work properly all dimensions(height width length) need to have the same unit of length
so first lets convert our height (which is 18 inches) into feet
every foot is 12 inches so:
18 inch ÷ 12=1.5 foot now we can the multiplication
3×2×1.5=9 cubic feet
