Please help!!!

The other answer on Chegg was incorrect so please redo!

For polonium, which was the first element discovered by Marie Curie, the ideal physical density in g/cm^3 is 9.32. Po has an amu of 209, and a simple cubic unit cell (interestingly, it is the only metal which has a SC unit cell at room temperature). Back-calculate to find the ideal radius of the Po atom, in units of nm (nanometers). Watch your units: there are 10^7nm in a cm.