4)psn a is located on equtor at long. 130e psn b is located 100nm from a on a bearing of 225 deg (t). The co-ordinates of b are
x = 225 - 180 = 45 deg
In triangle AOB
x = 45 deg
AO = OB (45 45 90 triangle)
dist AB = 100 nm
dist AO = dist OB AB Cos x = 100 x cos 45 = 70.7 nm
GC dist AO = 70.7 nm = d lat x 60
d lat = 70.7/60 = 1 deg 11 min
Latitude of B = 1 deg 11 min South.
departure dist OB = 70.7 nm = d long x 60 x cos lat
70.7 = d long x 60 x cos 1 deg 11 min = d long x 59.98
d long = 70.7/59.98 = 1 deg 10 min
Longitude of B = 130 E - 1 deg 10 min = 128 deg 49 min East.
Co ordinates of B (1*11' S 128*49' E)