1. The problem statement, all variables and given/known data Assuming the person weighs 980 N on the surface of the Earth, how would you use ratios to obtain the weight of a person at 128 000 km above the surface of the Earth. 2. Relevant equations Fg is proportional to 1/d2 3. The attempt at a solution The answer in the key says 0.072 N. I didn't know exactly where to start but by working backwards from the answer I have determined that it is 20 times the distance from the centre of Earth. I know how to solve these questions using ratios if I am given the times the distance from the centre of Earth. For example for a previous question: Three times the distance from the centre of Earth, here is how I solve it. Fg is proportional to 1/d^2 1x3 = 3 therefore 980 = 1/3^2 980 / 9 = 109 N This method works everytime when I am given the times the distance from the centre of Earth. But when I am given a specific distance I do not know how to get the answer. Can someone please help? Thanks!