Answer:
(a) 250º
(b) 310º
Step-by-step explanation:
I've attached an image of how I did it, and now I shall try my best to explain it in words...
A from B:
At B we can extend the line coming from A through the 130º angle.
From A we know that from the vertical, this line has an angle of 70º, so we can split the 130º angle into 70º and 60º.
Now we can extend the vertical at B downwards. This straight vertical line must have angles that add up to 180º. From this we can see that 130º + x = 180º, and x = 50.
Then from the angle rule 'vertically opposite angles are equal', we know that the angle to the left of the downward vertical must be equal to the one opposite and hence must be 70º also.
Now we add these angles up: 130 + 50 + 70 = 250º and this is the bearing to A from B.
B from C:
I've redrawn the triangle just for simplication.
Extend the line at B coming from C, and now using the same angle rule as earlier, we know that that anlge must be equal to the one opposite, which we already worked out to be 50º.
If we drawn a vertical at C, we know that the angle to the left of the vertical must also be 50º since it's made up of the same lines as at B.
Since we're finding the bearing, we now need to find the angle going clockwise: 360-50 = 310º and this is the bearing to B from C
