so you expect the "northings" to be negative
(+ means north, - means south)
and you expect the eastings to be negative
(+ = eastward, - = westward).
On the second leg (course = 340), the plane is heading between West (270) and North (360). Northings will be positive but eastings continue to be negative.
Total northings = sum of individual northings
= [ 11 * cos(220) ] +[ 15 * cos(340) ]
= -8.4265 + 14.0954 = +5.6689
Total eastings = sum of individual eastings
= [ 11 * sin(220) ] + [ 15 * sin(340) ]
= -7.0707 + -5.1303 = -12.2010
The resultant is found using the Pythagorean theorem:
distance = SQRT( 5.6689^2 + 12.2010^2) = 13.45 km
With a positive northing and a negative easting, you know that the plane has gone 13.45 km in a direction between west and north. The exact resultant direction can be found using the inverse of the tangent function:
Resultant course = arctan(12.2010/5.6689) = N 65 W = 360 - 65 = 295
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A "bearing" is a direction in which you observe something.
If a vehicle (plane or ship) is pointed in a direction for movement, it is called a heading. The direction that the vehicle actually follows - because the direction of the heading can be affected by wind or water currents - is called the course.
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On ships, North is 000 degrees (we always use three digits for headings and courses), East is 090, South is 180, West is 270 and NorthWest is 325. As you get closer and closer to North: 358, 359... 000.
On airplanes, North is called 360 (not 000) and as soon as you turn easward, it becomes 001, 002...
However, you may sometimes hear air people use only the first two digits (that is from the days of magnetic compass, where the third number was not always very sure). If you have an airport near you and it has a runway called "Runway 24", that means the runway is facing (roughly) the direction 240 degrees (magnetic).