🔍 Key Concepts

• Relationship between Greenwich Hour Angle (GHA) and geographic longitude • How to convert an angle measured west from Greenwich (0°–360°) into E/W longitude • What happens when GHA is greater than 180° and how that affects E or W longitude

💭 Think About

• First, picture the Earth with 0° at Greenwich and GHA measured westward all the way around to 360°. Where on that circle would a GHA of 215°15' lie? • Think about the meridian exactly opposite Greenwich (180°). How many degrees beyond that is 215°15', and in which direction? • Once you know how far past 180° the angle is, decide whether that location is better described as east or west longitude, and what its numerical value would be.

✅ Before You Answer

• Confirm that GHA is always measured westward from Greenwich from 0° to 360° • Determine how to express any GHA greater than 180° as an equivalent east or west longitude between 0° and 180° • Before picking a choice, double-check whether the final longitude should be east or west and whether you used the correct difference from 360° or 180°, not mixed up.