It actually gets you 1.36g, given the same density (your assumption) and using the fact that you are further away from the center of mass you get g ~ density x

It actually gets you 1.36g, given the same density (your assumption) and using the fact that you are further away from the center of mass you get g ~ density x radius [0] [0] https://en.wikipedia.org/wiki/Gravity_of_Earth#Depth https://en.wikipedia.org/wiki/Gravity_of_Earth#Depth