Kepler’s Third Law of planetary motion states that the square of the period T of a planet (the time it takes for the planet to make a complete revolution around the sun) is directly proportional to the cube of its average distance d from the sun.

a.) Express Kepler’s Third Law as an equation.

b.) Find the constant of proportionality by using the fact that for our planet the period is about 365 days and the average distance is about 93 million miles.

c.) The planet Neptune is about 2.79 x 10^9 mi from the sun. Find the period of Neptune.