Explanation:
It is given that,
A planet were discovered between the sun and Mercury, with a circular orbit of radius equal to 2/3 of the average orbit radius of Mercury.
Mass of the Sun, 
Radius of Mercury's orbit, 
Radius of discovered planet, 

Let T is the orbital period of such a planet. Using Kepler's third law of planetary motion as :




T = 4135214.625 s
or
T = 47.86 days
So, the orbital period of such a planet is 47.86 days. Hence, this is the required solution.
True, they had a hole in their hip socket that allowed them to run faster than other reptiles of their size at the time. As well as most reptiles besides reptiles had legs to the side, rather than under them like dinosaurs did.
Hope this helps!
A neutron star has more mass than a bowling ball,
and is about the same size as Chicago.