The figure shows an elliptical path of a planet around the sun such that the area of triangle is the area of the ellipse. (see figure) with as the major axis, and as the minor axis. If is the time taken for the planet to go over path and for path taken over then:
Kepler's third law states that the square of the period of revolution of a planet around the sun is proportional to the third power of the average distance between sun and planet i.e., , here is constant. If the masses of sun and planet are and respectively then as per Newton's law of gravitation force of attraction between them is , here is gravitational constant. The relation between and is described as:
