In an experiment using the Cavendish balance, the smaller spheres have a mass of `5.0xx10^(-3)`kg each, the larger spheres have a mass 12.0 kg each, the length of the rod is 100.0 cm, the torsion constant of the fibre is `3.56xx10^(-8)` Nm per rad, the angle of twist is `4.86xx10^(-3)`rad, and the distance between the centres of each pair of heavy and light spheres is 15.0 cm. Compute the value of the gravitational constant G from this data.