r1M1=r2M2r_{1} \sqrt{M_{1}}=r_{2} \sqrt{M_{2}}r1M1=r2M2
r∝1M\mathrm{r} \propto \frac{1}{\mathrm{M}}r∝M1
r1r2=M1M2\frac{r_{1}}{r_{2}}=\frac{\sqrt{M_{1}}}{\sqrt{M_{2}}}r2r1=M2M1
r∝Mr \propto \sqrt{M}r∝M