math
posted by T .
a plane with an airspeed of 192mi/h is headed on a bearing of 121 degrees. a north wind is blowing (from north to south) at 15.9 mi/h . find the ground speed and the actual bearing of plane.

I will assume you are using the standard 'true north' reference and a clockwise rotation resulting a vector in the fourth quadrant with a magnitude of 192.
draw a vector from the end of the previous vector due south with a magnitude of 15.9
draw in the resultant vector
by cosine law:
R^2 = 192^2 + 15.9^2  2(192)(15.9)cos 121º
R will be the ground speed.
Use the Sine Law to find the angle across from the 15.9 side, add that angle to 121 and you have your actual bearing. 
is it gonna be right traingle or what?

*
* *
15.9 * 121 *
* *
*))90 (( *
**************
192 
10.76