Kepler's 1-2-3 law
Another formulation of Kepler's third law, that relates to the mass m of the primary to a secondary's angular velocity omega & semimajor axis a:
m o= omega^{2} a^{3}.
Kepler's laws (J. Kepler)
Kepler's first law
A planet orbits the Sun along with the Sun at one focus in an ellipse.
Kepler's second law
A ray directed from the Sun to a planet sweeps out equal areas in equal times.
Kepler's third law
The square of the period of planet's orbit is proportional to the cube of that planet's semimajor axis; the constant of proportionality is the similar for all planets.