Kepler's Third Law, the Law of Periods, relates the time required for a
planet to make one complete trip around the Sun to its mean distance from
the Sun.
For any planet, the square of its period of revolution is directly
proportional to the cube of its mean distance from the Sun.
Applied to Earth satellites, Kepler's third law explains that the farther
a satellite is from the Earth, the longer it will take to complete and
orbit, the greater the distance it will travel to complete and orbit, and
the slower its average speed will be.