🔍 Key Concepts

• Mid-latitude sailing formula for course and distance between two positions • How to find difference of latitude (DLat) and difference of longitude (DLo), and then apply mid-latitude • Using the cosine of mid-latitude to convert DLo in minutes to difference of longitude in miles (departure)

💭 Think About

• First, compute the difference in latitude and decide if it is north or south, then convert it to minutes of arc so you can use it in distance calculations. • Find the mid-latitude between the two positions, and recall how the cosine of this mid-latitude enters into the mid-latitude sailing formulas for course and distance. • Once you have DLat and the departure, think about which right triangle you are solving and which trigonometric function (tan, sin, or cos) gives you the course angle from those two sides.

✅ Before You Answer

• Be sure you are using mid-latitude, not initial or final latitude, when taking the cosine for DLo to miles conversion. • Confirm that your DLo is correctly converted to minutes and that you have the correct east/west direction so the sign is right. • After computing distance and course, compare your numerical values (both the angle and the distance) to the choices and see which one matches best, paying attention to tenths.