Hover or tap underlined Spanish terms to see their translation and exam tip.
Encontrándonos con nuestra embarcación en la oposición Isla Tarifa – Punta Alcázar, tomamos simultáneamente demora de aguja a Isla Tarifa= 344º y demora de aguja a Punta Cires= 117, 5º. Se pide calcular la situación verdadera.While on the Isla Tarifa–Punta Alcázar opposition line, you simultaneously take compass bearings Da Isla Tarifa = 344º and Da Punta Cires = 117.5º. Calculate your true position:
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Correct answer: a) l = 35º 57.8' N; L = 005º 35.8' W.
Why it is correct
On the Isla de Tarifa–Punta Alcázar opposition line, the true bearing towards Isla de Tarifa is Dv = 345º, so Ct = 345º − 344º = +1º. The true bearing to Punta Cires is Dv = 117.5º + 1º = 118.5º, which intersects the opposition line at l = 35º 57.8′ N, L = 005º 35.8′ W.
Why the others are not
- b) Does not match the intersection of the Tarifa–Alcázar opposition with Dv(Cires) = 118.5º.
- c) Does not match the intersection of the Tarifa–Alcázar opposition with Dv(Cires) = 118.5º.
- d) Does not match the intersection of the Tarifa–Alcázar opposition with Dv(Cires) = 118.5º.
How to work it out in the exam
- Find Ct = 345º − 344º = +1º on the Tarifa–Alcázar opposition and correct Dv(Cires) = 117.5º + 1º = 118.5º.
- Intersect the Tarifa–Alcázar line with the reciprocal 298.5º from Punta Cires: 35º 57.8′ N, 005º 35.8′ W.
Where this question comes from
- Ministerio de Transportes (Madrid) · 2025 · Convocatoria de junio · PER Test 1 · question 43 Official paper · Official answer key
- Ministerio de Transportes (Madrid) · 2025 · Convocatoria de junio · PER Test 2 · question 42 Official paper · Official answer key
Try it: Navigation calculations
Pending instructor review. Machine translation, not reviewed.