If you have two spheres, one of them has a mass of 100 and a surface area of

100, and the other one has a surface area that is 70% less than the first

and has the same density, how much mass will the second sphere have?

I'm looking into this hypothesis (for fun ONLY) that when all the continents

were together, they made up the entire surface of the earth, and their

splitting and drifting apart was caused as the earth somehow expanded.

Please don't feel the need to debunk that theory, I'm taking it with a grain

of salt. I just want to figure out how much the earth has increased in mass

if that hypothesis is true and if the density has remained constant, but I

don't know how.