According to Kepler's Third Law, the orbital period T of a planet is related to the radius R of its orbit by T2 is proportional to R3. Jupiters orbit is larger than Earth's by a factor 5.19. What is jupiters orbital period? (Earths orbital period is 1 year). Any help is appreciated, this is question 9 from Chapter 1 in Giambattista Physics, soultion is 11.8 years but i need help getting to that point. According to Kepler's Third Law, the orbital period T of a planet is related to the radius R of its orbit by T2 is proportional to R3. Jupiters orbit is larger than Earth's by a factor 5.19. What is jupiters orbital period? (Earths orbital period is 1 year). Any help is appreciated, this is question 9 from Chapter 1 in Giambattista Physics, soultion is 11.8 years but i need help getting to that point.