the orbital period of the moon is 27.32 days. The international space station has an orbital period of 90 minutes. What is the mean distance between the center of the earth and the center of the international space station?

Question

the orbital period of the moon is 27.32 days. The international space station has an orbital period of 90 minutes. What is the mean distance between the center of the earth and the center of the international space station?
moons orbital radius: 25,201

bobpursley · Answer

Isn't this Kepler's Law?

Period^2=contant*radius^3
and as a ratio
PeriodISS/PeriodMoon = (radiusISS/radiusmoon)^3

change the periods to the same units, I would do hours for both, but it does not matter which you choose.