🔍 Key Concepts

• Relationship between difference of longitude (DLO), distance, and departure when steaming due east or west • How many nautical miles correspond to 1 minute and 1 degree of longitude at a given latitude • Converting from degrees East through 180° to degrees West on the Earth’s 360° circle

💭 Think About

• When you steam due east (090°), which coordinate(s) change: latitude, longitude, or both? Why? • How can you use the departure formula with the cosine of the latitude to find the difference in longitude covered by 905 miles? • After finding the total change in longitude from 174°06'E, do you cross the 180° meridian? If so, how do you express the new longitude correctly as East or West?

✅ Before You Answer

• Confirm you are using departure = distance × cos(latitude) and that your latitude is in the correct form for the cosine function • Ensure you convert the resulting difference of longitude into degrees and minutes correctly from nautical miles • Check how to convert from an eastern longitude past 180° into the equivalent western longitude before picking a choice