A geosynchronous orbit is an orbit about the Earth with orbital period exactly equal to one sidereal

A geosynchronous orbit is an orbit about the Earth with orbital period exactly equal to one sidereal day. A circular geosynchronous orbit above the Earth’s equator is called a geostationary orbit, because the orbiting object remains in a fixed position in the sky as observed from a fixed position on the ground. What is the semi major axis of a geosynchronous orbit (express your answer in terms of Earth radii)