[the volume of the stack of books]=[area of each book]*[<span>height of the stack] </span>area of each book=63 in² height of the stack=15.75 in <span>so </span>[the volume of the stack of books]=[63 in²]*[15.75 in]=992.25 in³<span>
Each rectangular book represents a cross-section of the stack. Using Cavalieri's Principle, the area of a cross-section times the height equals the volume.