GPS (Global Positioning System) satellites orbit at an altitude of 2.0×10^7 m. Find the orbital period.(hours) I use the equation T=(2pi/sqrt(GM))r^(3/2). Shouldnt that be the correct way of doing it? I know im supposed to add the altitude to the radius of the earth, G is known, M of earth is known. I just dont understand where I am going wrong with this. It should be a simple problem yet I am not able to get the correct answer. is it possible im doing something as silly as not converting something somewhere? If anyone could offer some help, it would be greatly appreciated.