The volume of a rectangular prism is:

Where l, w, and h represent the length, width, and height of the prism. The base of the prism is essentially just the width times the height, so that part is already done for us. All we have left to do is to multiply the height to the base.
160 x 32 =
5120 m³ should be the volume of the cereal box.
Hope this helped! ^-^