calculus
posted by ASH .
A plane flies 810 miles from A to B with a bearing of 75 degrees. Then it flies 648 miles from B to C with a bearing of 32 degrees. Find the straightline distance from and bearing from C to A.

actually, planes fly on headings, not bearings.
Setting A at (0,0), B is at
(810 sin 75, 810 cos 75) = (782,210)
moving from B to C adds another
(648 sin 32, 648 cos 32) = (343,550)
so C is at (1125,760)
distance is 1358
heading from C to A is 236