Part Three 1. Based on your results from parts one and two, you have determined relationships between the force of gravity, the masses involved, and the distance between the masses. Put all of these together in one proportionality. (If you get stuck, find the force value for 20 kg masses with 2 m between the masses - what does this value tell you about how they all relate?) 2. Plug in values for the force of gravity, mass 1, mass 2, and the distance into the proportion. You should now be finding the proportionality constant, which makes your proportion an equality. 3. Write Newton's law of universal gravitation