A vessel at LAT 28°20'N, LONG 16°00'W is to...

Question 1 / 2707066636eea28f7522a1c51b7c8

Question 1 of 2707066636eea28f7522a1c51b7c8

A vessel at LAT 28°20'N, LONG 16°00'W is to proceed to LAT 21°00'N, LONG 18°00'W. What is the course and distance by mid-latitude sailing?

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Question 1 of 27070

A vessel at LAT 28°20'N, LONG 16°00'W is to proceed to LAT 21°00'N, LONG 18°00'W. What is the course and distance by mid-latitude sailing?

🔍 Key Concepts

• Mid-latitude sailing formulas for course and distance • How to find difference of latitude (DLat) and difference of longitude (DLon), including E/W sign • Using cosine of mid-latitude to convert DLon (in minutes) to departure

💭 Think About

• First, compute DLat between the two positions, being careful with N/S, and convert it to minutes of arc. Is it getting more southerly or more northerly? • Next, compute DLon in minutes of arc and decide if it is easterly or westerly. Then adjust DLon using the cosine of the mid-latitude to find departure. • Use the right-angle triangle formed by DLat and departure to find the course (with arctangent) and the distance (with Pythagoras). Then compare your results to the choices given.

✅ Before You Answer

• Be sure you used the mid-latitude (average of the two latitudes) in degrees, not in minutes, before taking the cosine. • Check that your quadrant for the course makes sense: are you going south or north, east or west from the initial position? • Verify your final distance is in nautical miles and that you used DLat and departure (both in minutes) correctly in the Pythagorean formula.

Question 1 of 27070

A vessel at LAT 28°20'N, LONG 16°00'W is to proceed to LAT 21°00'N, LONG 18°00'W. What is the course and distance by mid-latitude sailing?

194.0°T, 453.0 miles

197.3°T, 448.0 miles

196.8°T, 450.0 miles

195.2°T, 451.0 miles

Question 1 / 2707066636eea28f7522a1c51b7c8

Question 1 of 2707066636eea28f7522a1c51b7c8

A vessel at LAT 28°20'N, LONG 16°00'W is to proceed to LAT 21°00'N, LONG 18°00'W. What is the course and distance by mid-latitude sailing?

Back

Question 1 of 27070

A vessel at LAT 28°20'N, LONG 16°00'W is to proceed to LAT 21°00'N, LONG 18°00'W. What is the course and distance by mid-latitude sailing?