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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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Another possible solution Comment 4 of 4 |
https://www.marksmath.org/classes/common/MapProjection.pdf

This document gives the mathematics behind the Mercator projection and why it preserves angles.

• Mercator: T(ϕ,θ) = (θ,ln(|sec(ϕ) + tan(ϕ)|))

A latitude 16S gives a distance 0.28295 south of the equator on the rectangular map whereas 41N gives 0.78586.

Now that things are flat, the arctangent should work:

arctan((0.28295+0.78586)/(2pi)) = 9.6540 degrees

  Posted by Jer on 2024-07-31 08:34:41
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