Question

A bird is flying from A towards B at an angle of 35°, a point 30 km away from A. At B it changes its course of flight and heads towards C on a bearing of 48° and distance 32 km away. How far is B to the West of A?

(sin 55° = 0.8192, cos 55° = 0.5736, sin 42° = 0.6691, cos 42° = 0.7431)

Answer 1

Distance from B to the west of A is AB’

In ∆ABB’

cos 55° = `"AB’"/"AB"`

0.5736 = `"AB’"/30`

∴ AB’ = 0.5736 × 30

= 17.21 km

Distance of B to the West of A is 17.21 km