General Navigation USCG Question #2274 (Set 69)

A great circle crosses the equator at 93°W. It will also cross the equator at what other longitude?

Official USCG Answer & Rule Citation

Correct Answer: Option C — 87°E

Antipodal equatorial crossings on a great circle track are separated by 180 degrees of longitude. Subtracting 93°W from 180° results in 87°, reversing the hemisphere to East (87°E), per navigational math standards outlined in Bowditch.

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