I made exactly the same mistake that you made! . . . LOL
I too had my ship moving east !
Gee, I hope no one saw that . . .
A lighthouse is 10 km north-east of a ship travelling due west at 16 km/h.
i) How far is the ship from the lighthouse 45 min later?
ii) What is the bearing of the light-house from the ship at this time?
I used the cosine side formula…
Which is wrong because the answers say it’s 20.3 km.
I used the cosine angle formula:
cos B = 55 degrees
Bearing = 270 + 55
=325 degrees T
Which is also wrong according to answer (070 degrees T)
Could someone please please show me how to do this question?