Answer:
Orbital period, T = 1.42 years
Step-by-step explanation:
It is given that,
Orbital period of a solar system planet,

The orbital period of the planet can be calculated using third law of Kepler's. It is as follows :

M is the mass of the sun



r = 1.42 AU
So, the solar-system planet that has an orbital period of 8 years would have an orbital radius of about 1.42 AU.