A comet has a perihelion distance of 0.29 A.U. and an orbital period of 77 years. To the nearest thousandth of an A.U., what is its aphelion distance from the Sun? I know that keplers third law plays a part in this p2=a3 but I just can't plug it in right. I know the answer is 35.908 but I don't know how to get to that point.