Through the surface of a cone, masses and diameters of the four planets, Mercury, Mars, Venus, and Earth, are connected in an equation that is similar to those linking the Sun and its planets. Growth of Mercury, Mars, and Venus is coupled with Earth. The three growth curves in the figure are almost identical to those for Jupiter, Neptune, and Uranus. An additional figure in the chart describes the growth end and the mass-diameter stability. The terrestrial planets are approximately 5% older than the gas giants.