The weight of an object is the same on two different planets. The mass of planet A is only forty-five percent that of planet B. Find the ratio rA/rB of the radii of the planets.

Answer 1

mA/rA^2 = mB/RB^2 since the weights are equal.

rA^2/rB^2 = mA/MB = 0.45
rA/rB = sqrt(0.45) = 0.671

Answer 2

0.671