Determine the density of a planet in SI units

[surfingian]

Homework Statement

Determine the density of fictional planet in SI units from the information

Homework Equations

Planets mass 1.28x10^22 Kg divided by radius 1.12x10^3Km = 1.14x10^25 Kg/m3

The Attempt at a Solution

My answer seems all wrong, the SI unit should be in Kg/m cubed. Is radius equal to the volume as I feel that this is where the calculation went wrong, or maybe what I have got is right.

 

[tiny-tim]

welcome to pf!

hi surfingian! welcome to pf!

density is per volume

 

[MrWarlock616]

The radius is not the volume. $Volume=\frac{4}{3} \pi r^3$