To solve the problem shown above you must apply the proccedure shown below:
1. You must apply the Kepler's third law, as below:
(T1/T2)²=(R1/R2)³
T1 and T2 are the orbital periods. (T1=1 year; T2=5 years)
R1 and R2 are the orbital radius. (R1=1 Astronomical unit)
2. Now, you must substitute the values shown above into the formula and clear R2:
(1/5)²=(1/R2)³
1/25=1/R2³
R2³/25=1
R2³=25
R2=∛25
R2=2.92 AU
Therefore, the answer is: 2.92 AU
