1 The geosynchronous satellite is running over the equator of the earth.

Its motion is gravity provide by centripetal force:

GMm/r^2=m(2pi/T)^2r

M is the mass of the satellite, m is the mass of the earth, r is the distance from the satellite to the center of the earth, and t is the time of the earth for 24 hours a day.

M can be omitted, that is, the given mass in your question has nothing to do with the radius.

You can know by your own calculation:

Synchronous satellites have the same radius.