Here's a pic of the situation......

A = Tortuga
B = Captain Jack's initial position
C = fishing vessel
The distance from the wreck to Tortuga = about 52.91 miles
BTW....this could be solved with the Law of Cosines, thusly....
AC = sqrt [ 20^2 + 40^2 - 2(20)(40)cos(120) ]
I just thought that the pic kinda' brought it all home a little better....!!!
