Volume of a cube =a3 Calculation: Let the original edge length be ' a '. Original volume =a3 If the edge is tripled, new edge length =3a New volume =(3a)3 ⇒ New volume =27a3 The increase in volume = New volume ∕ Original volume ⇒ Increase in volume =27a3∕a3 ⇒ Increase in volume =27