1) r/l track btw a(45n 10w) and b(48'30n 15w) is
RL track from A to B is 270 + x deg
In triangle AOB
departure dist AO = d long in min x cos 45 = 5 x 60 x cos 45 = 212 nm.
great circle dist BO = (48.5 - 45) x 60 = 210 nm
tan x = BO/AO = 210/212
x = tan inv 210/212 = 44.7 deg
RL track = 270 + 44.7 = 314.7 deg