You depart LAT 33°45.0'N, LONG 118°30.0'W,...

Question 1 of 2707066636eea28f7522a1c51b06f

You depart LAT 33°45.0'N, LONG 118°30.0'W, and steam 2216 miles on course 250°T. What is the longitude of your arrival by Mercator sailing?

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Question 1 of 27070

You depart LAT 33°45.0'N, LONG 118°30.0'W, and steam 2216 miles on course 250°T. What is the longitude of your arrival by Mercator sailing?

🔍 Key Concepts

• Mercator sailing formula for difference of longitude using meridional parts and course/ distance • Relationship between departure, course angle from the meridian, and difference of longitude • How to convert an arc distance in nautical miles to difference of latitude on a great circle (1' = 1 NM)

💭 Think About

• First, from the given distance and course, what are the north-south and east-west components of your track? Think in terms of difference of latitude vs. departure. • Given that you start at 33°45.0'N and are on a southwesterly course (250°T), are you ending at a higher or lower latitude? Estimate the sign and rough size of the change in latitude. • Once you have the new latitude, how does Mercator sailing let you turn your departure into a difference of longitude? What table or function do you need at the mean latitude or with meridional parts?

✅ Before You Answer

• Confirm whether the course angle used in your trigonometric functions is the angle from north/south or from east/west; Mercator sailing uses the angle from the meridian. • Make sure you convert between miles and minutes of latitude correctly when finding difference of latitude (1 NM = 1'). • Before choosing an answer, check that your final longitude is still West and that the numerical change in longitude matches the size of your computed departure and the latitude you ended up at.