1. The problem statement, all variables and given/known data In January 2006, astronomers reported the discovery of a planet comparable in size to the earth orbiting another star and having a mass of about 5.5 times the earth's mass. It is believed to consist of a mixture of rock and ice, similar to Neptune. Take mass earth 5.97 x 10 ^24 and radius earth 6.38x10^6. If this planet has the same density as Neptune (1.76 g/cm^3), what is its radius expressed in kilometers? What is its radius expressed as a multiple of earth's radius? 2. Relevant equations D=MV 3. The attempt at a solution My attempt: I got (5.97x10^24kg earth's mass / 6380 km earth's radius) x (.00176 kg mass of unknown planet mass / x the radius of the unknown planet) = 1.068676422 x 10^-21 The answer does not seems right, I did convert each unit accordingly. Please and thank you in advance.