I'll tell you how to do it but you must crunch the numbers.
Use Kepler's 3rd Law
T^2 = k R^3
where k = 4(pi)^2/ GM
G =gravitational constant = 6.67300 × 10-11 m3 kg-1 s-2
M = mass of this new planet
pi = 3.14159265
T =3.09 days = 266976 seconds
R = (579,000,000km)/9 = 64333333.3 km
a)
Solve Kepler's 3rd Law for M. Your answer will be in kg
b)
mass of the sun = 1.98892 × 10^30 kilograms
Form the ratio
M(planet)/M(sun)
