F.3數學(三角比的應用)

A typhoon (at location B) is observed 300km away from a city
(at location A) at the bearing of S75(degree)E. This typhoon
moves at a bearing of N40(degree)W at 18km/h. It is known
that the area within 200km from the centre of the typhoon
will be affected by the typhoon. Will this city be affected
by the typhoon? If it does, how long will it be affected?