Mars orbits the sun at a mean orbital radius of 228e9 m and has an orbital period of 687 d. Earth orbits teh sun at a mean orbital radius of 149.6e9 m. a)The earth-sun line sweeps out an angle of 360 degrees during one earth-year. Approximately what angle is swept out by the Mars-sun line during one Earth-year? b) How frequently are Mars and the sun in opposition (on diametrically opposite sides of Earth)? I do not know any relavant equations or even how to begin this problem we were given this homework as we walked out of the room without covering all of the necessary material. Any help would be greatly appretiated. Thank you.