I don't even know what to do. It was in the section with law of cosines/sines. does this problem apply some how & I just don't know?

A ship is sailing due north. At a certain point the bearing of a lighthouse is N36.6degrees E and the distance is 11.5. After a while, the captain notices that the bearing of the lighthouse is now S46.5degrees E. How far did the ship travel between the two observations of the lighthouse.