If I remember rightly...
Draw the line from point A to B, which becomes the hypotenuse of a right angled triangle.
Remember that going North to South and vice versa that: 1' = 1 nm
and that the East to West part of the triangle you have drawn is the
DEPARTURE.
This is where they try and catch you out! 
(Remember: Departure = Change of Longitude in minutes x cosine latitude)
These should give you the horizontal and vertical dimensions of the triangle, which you can then punch into the basic trigonometrical equations. (SOH, CAH, TOA)
I guarantee that one or two of these will crop up in your General Navigation exam.
Just remember to use the Departure formula for the horizontal bit of the triangle!
Let me know if it works!
