State Kepler's Laws of planetary motion.

Explanation

Law of orbits (1st Low) : All planets will move in elliptical orbits with the sun lies at one of its foci.
Law of areas (2nd law): The line that joins any planet to the sun sweeps equal areas in equal intervals of time, i.e., `(triangleA)/(triangleT)`=constant. i.e., planets will appear to move slowly when they are away from sun, and they will move fast when they are nearer to sun.
Law of periods (3rd law): The square of time period of revolution of a planet is proportional to the cube of the semi marjor axis of the ellipse traced out by the planet.
`i.e.,T^2 propR^3" or "(T^2)/(R^3)`= constant.