1. The problem statement, all variables and given/known data Using astronomical units as the unit of length , years as the time , and the mass of the Sun as the unit of mass , the value for k in kepler's third law is 1. In these units , what is the value of Newton's constant of gravitation G? 2. Relevant equations P^2 =k*a^3 P^2= 4*pi^2*a^3/(G(m(1)+m(2)) Possibly k=4*pi^2/G*M(sun) P is the period 3. The attempt at a solution since k = 1 and k =4*pi^2/G*M(sun), all I have to do is switch variables. k=4*pi^2/(G*M(sun)) => 4*pi^2/(M(sun))=G , but I found that method to be a problem because the G I calculated isn't equal the universal Gravitational constant we are all familar with.