Well we know that: Volume = l×w×h so that means: 40 = l×w×h Well if the length is doubled that means New Volume = 2l×w×h or New Volume = 2×l×w×h Well since we know from our original equation that 40 = l×w×h, we can substitute it into this new volume equation New Volume = 2×l×w×h New Volume = 2×(40) New volume = 80 cm³