Two satellites S_1 and S_2 are revolving in circular orbits around a planet with radius R_1=3200 km and R_2=800 km respectively. The ratio of speed…

Two satellites $\displaystyle S_1$ and $\displaystyle S_2$ are revolving in circular orbits around a planet with radius $\displaystyle R_1=3200 \mathrm{~km}$ and $\displaystyle R_2=800 \mathrm{~km}$ respectively. The ratio of speed of satellite $\displaystyle S_1$ to the speed of satellite $\displaystyle S_2$ in their respective orbits would be $\displaystyle \frac{1}{x}$ where $\displaystyle x=$ \_\_\_\_.