The position of two towns A and B on the earth’s surface are (360N,490E) and (360N,1310W) respectively.(a) Find the difference in Longitude between A and B. (b) Given that the radius of the earth is 6370km, calculate the distance between town A and town B. (c) Another town C is 840km east of town B and on the same latitude as towns A and B. Find the longitude of town C.