Question

A star is estimated to have a mass of 2 X 10^36 kg. Assuming it to be a sphere of average radius 7.o X 10^5 km. Calculate the average density of the star in units of grams per cubic centimeter

Answer 1

Since you want density unit in g/cc, I would adjust the starting units, like so.
7.0 x 10^5 km = 1.0 x 10^10 cm (It's easier to do this at the start than at the end for me.)

The volume of a sphere is (4/3)*pi*r³ = ?? cc

Then mass = volume x density.
Convert mass to grams and solve for density.