For satellites moving in circular orbits around Earth, the relation T2=kr3 holds, where T is the orbital period and r the orbital radius.
(i) A satellite with period 24h orbits at a radius of 4.24×107m. Taking T in hours and r in metres, calculate the numerical value of the constant k.
(ii) Using the value of k obtained in part (i), find the orbital radius (in kilometres) required for a satellite to have a period of 90min.