Hi guys.
Im a bit stuck on this bearing question and need a bit of help.

At 12:00 the captain of a ship observes that the bearing of a lighthouse is 340'. His position is
at A.
At 12:30 he takes another bearing of the lighthouse and finds it to be 030'. During this time
the ship moves on a constant course of 280' to the point B.
His plot on the chart is as shown in Fig 11 below.
http://i137.photobucket.com/albums/q.../MathsHelp.jpg
(i) Write down the size of the angles LAB and LBA.

I worked out LAB to be 60' because i knew that the course to be was 280' which was pretty easy. Im really stuck on angle LBA though. Any suggestions?