Chart Navigation & Plotting · Position — Difference of Longitude
A vessel moves from 070°20'W to 068°50'W. The difference of longitude is:
- A1°30' east✓ Correct
- B1°30' west
- C2°10' east
- D0°30' west
Explanation
070°20'W to 068°50'W is a decrease in west longitude of 1°30', meaning the vessel moved eastward. dLong = 1°30' (90') to the east.
Authority: Bowditch (Pub. No. 9)
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