A plane was flying at 200knots left an airport A(30°S,31°E)and flew due north to an airport B(30°N,31°E).after a 15 mins stopover at b the plane flew due west to an airport c(30°n,13°e) at the same speed.calculate the total time taken to complete the journey grom airport a to airport c, through airport b.
going N/S the radius is just R, the radius of the earth, R
going E/W, at latitude θ, the radius is R cosθ