text: I'm not going to do the problem for you, because this is obviously homework. \n\nWhat I will do, is tell you that you should use the law of cosines. \n    b^2 = a^2 + c^2 - 2ac * cosB\n\nGiven the first two directions of the boats, you can find the angle opposite side b.  And you are already given the other two sides.  Once you figure out angle B, it is just plug and chug.\n\nhope this is helpful!