Answer:
Planet Y
Rx = 1.587 Ry
Explanation:
Tx = 290 days
Ty = 145 days
Let the semi major axis of planet X is Rx and of plant Y is Ry.
According to the Kepler's third law of planetary motion
[tex]\frac{T_{x}^{2}}{T_{y}^{2}}=\frac{R_{x}^{3}}{R_{y}^{3}}[/tex]
[tex]\frac{290^{2}}{145^{2}}=\frac{R_{x}^{3}}{R_{y}^{3}}[/tex]
[tex]4=\frac{R_{x}^{3}}{R_{y}^{3}}[/tex]
[tex]1.587=\frac{R_{x}}{R_{y}}[/tex]
Rx = 1.587 Ry
So, planet Y is closest to star.
