1. The problem statement, all variables and given/known data The mass of the earth is 5.98*10^24 kg and its radius is 6370 km. The radius of the moon is 1738 km. The acceleration of gravity at the surface of the moon is 1.62 m/s^2. What is the ratio of the average density of the moon to that of the earth ? 2. Relevant equations New's law of gravity: F= G*m1*m2/r^2 3. The attempt at a solution I understand that I need to find mass of the moon to get its density. How should I calculate the mass of the moon ??