Hover or tap underlined Spanish terms to see their translation and exam tip.
Calcular la mínima distancia que separa los puntos de la superficie terrestre de coordenadas 25º 43' S, 110º 17' E y 45º 58' S, 156º 39' W.Calculate the shortest distance separating the points on the Earth's surface at 25º 43' S, 110º 17' E and 45º 58' S, 156º 39' W.
Show the answer
Correct answer: a) 4430'
Why it is correct
The shortest distance on the sphere is the great-circle distance. With ΔL = 360º − (110º 17′ + 156º 39′) = 93º 04′ and both latitudes south, cos D = sin(25º 43′) sin(45º 58′) + cos(25º 43′) cos(45º 58′) cos(93º 04′) = 0.27846, giving D = 73.832º = 4430′.
Why the others are not
- b) Adds the second term instead of subtracting it when ΔL > 90º.
- c) Corresponds to the rhumb-line distance, which is longer than the great-circle minimum.
- d) Does not match the spherical law of cosines.
How to work it out in the exam
- The shortest terrestrial distance is the great circle: multiply D in degrees by 60.
Where this question comes from
- Junta de Andalucía · 2024 · 2ª convocatoria · CY Módulo de navegación · question 13 Official paper · Official answer key
Pending instructor review. Machine translation, not reviewed.