🔍 Key Concepts

• Great circle definition on a sphere • Relationship between great circles and the Earth’s meridians (longitude lines) • How longitude is measured east and west from the Prime Meridian (0°)

💭 Think About

• If a great circle crosses the Equator at one longitude, how is the other crossing point related to it on a globe? • What is the total number of degrees around the Earth, and how does that help you find a point directly opposite on the Equator? • How do you correctly convert between east and west longitudes when you move to the opposite side of the Earth?

✅ Before You Answer

• Remember that a full circle around the Earth is 360°, so opposite points differ by 180° in longitude. • Be sure to switch from E to W (or W to E) when you move 180° around the globe. • After you compute the opposite longitude, compare it carefully with the multiple-choice options and match both the degrees and the E/W direction.