Trigonometry law of cosine
posted by NEED HELP ASAP on .
A plane is flying with an airspeed of 200 miles per hour and heading 150°. The wind currents are running at 30 miles per hour at 175° clockwise from due north. Use vectors to find the true course and ground speed of the plane. (Round your answers to the nearest ten for the speed and to the nearest whole number for the angle.)

draw the diagram. Add the wind vector to the speed vector (head to tail). The resultant from the origin to the head of wind is now the resultant. Label it R.
You have two sides, and the angle between S and W. Figure it out. I see it as in my head as the 36030175 =155 check that.
R^2=200^2 + 30^2  2*200*30Cos155
grab your calculator, and find R 
A plane fre