1. The problem statement, all variables and given/known data OK here's the question: What is the period of a planet orbiting 3 A.U. from a star 3 times as massive as the sun? And my teacher says to use keppler's 3rd law revised by newton but im completly confused by the equation and how to use it on this problem. 2. Relevant equations P^2= 4*pi^2/G(m1+m2) * R^3 is the equation 3. The attempt at a solution I have no idea where to even begin... please help. Suggestions?