1. The problem statement, all variables and given/known data The Moon is 3.9*10^5 km from Earth's center and 1.5*10^8 km from the Sun's center. The masses of Earth and the Sun are 6*10^24 and 2*10^30 kg, respectively. a. The ratio of the gravitational fields due to the Sun and Earth at the center of the moon is: 1) 2300 2) 230 3) 23 4) 2.3 < Correct answer b. When the Moon is in its third quarter phase, its direction from Earth is a right angles to the Sun-Earth direction. The net gravitational field due to the Sun and Earth at the center of the Moon is?: 1) 6.4*10^-3 m/s^2 2) 6.4*10^-6 m/s^2 3) 6.4*10^-8 m/s^2 4) 6.4*10^-10 m/s^2 2. Relevant equations Fg=G(m1*m2)/r^2 3. The attempt at a solution I attached a picture of the diagram I drew. I tried to resolve the forces in the X-Y Coordinates but I didn't know what to do from there; I still didn't know the mass of the Moon so I couldn't get a pure answer like the ones given in the choices.