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The rhumb line track from A (53° 50’N 007° 55’E) to B (53° 00’N 003° 00’E) is 250°. Calculate the initial great circle track.
  • A
    247°
  • B
    253°
  • C
    248°
  • D
    252°

Convergency is the angle of inclination between two meridians at given latitude.

Convergency = Change in Longitude × (Sine Mean Latitude)

The difference between great circle direction and rhumb line direction joining two points is called conversion angle and it is equal to half of the convergency for the same two points.

Conversion angle = ½ Convergency

Chart convergence = 4º55’ x sine (53º25’) = 4º
Conversion angle = 2º
GCT at A = 250 + 2º = 252º

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