A great circle crosses the equator at 127°W. It will also cross the equator at what other longitude?

Correct Answer: Option D — 53°E

Great circles are the intersection of the earth's surface with a plane passing through its center, forming a complete circle. Because they are symmetrical and bisect the globe, a great circle crossing the equator at 127°W will intersect it again exactly 180 degrees away, at 53°E.