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Around the World in 80 Hours (Posted on 2024-07-30) Difficulty: 3 of 5
Phileas Fogg III wants to commemorate his grandfather's circumnavigation by going around the world in 80 hours. This will be by airplane, and he wants to start out at 16° South, travel somwhat north of east maintaining a constant direction bearing, and end up at the same longitude at latitude 41° North. This sort of path (constant direction bearing) is called a loxodrome, which maps as a straight line on a Mercator projection.

What should that constant direction bearing be?

See The Solution Submitted by Charlie    
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Solution Possible solution | Comment 1 of 4
If I understand correctly, a Mercator projection is the mapping of a sphere onto a cylinder of the same equator.  The cylinder is then unrolled.

We can let the Earth have a radius of 1 unit.  The start is tan(16) below the equator.  The finish is tan(41) above the equator.  The distance parallel to the equator is the length of the equator: 2pi.

The angle is then arctan((tan(16)+tan(41))/(2pi)) = 10.425 degrees N of E. 

  Posted by Jer on 2024-07-30 09:22:26
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