Tb / Ta = ?????? i have a final question, which is how do i find this. i know what the question is askin i just dont understand how to get the answer Two planets A and B, where B has twice the mass of A, orbit the Sun in elliptical orbits. The semi-major axis of the elliptical orbit of planet B is two times larger than the semi- major axis of the elliptical orbit of planet A. What is the ratio of the orbital period of planet B to that of planet A?