First we understand what directional angles are and where they are on our outline

1. Look at your outline

2. directional angles are angles that report from the north direction of the grid to the direction of the object, clockwise, from 0 to 360. You go from point A to point B, therefore point B is your object (vector AB - shows the direction to the object). Blue - marked north. Black marks the directional angle of the line AB – α_АВ.

3. Directional angles can be right and left.. If you follow the arrow, then you reach point B, then the angle marked in green is on your right, which means it is the right directional angle of line B1.

And on the other hand there will be a left directional angle for line B1 (marked in red)

4. Now imagine that you have reached point 1 and then go to point 2 along line 12. From here, the right directional angle of line 12 is marked in yellow.

5. Imagine walking along an orange arrow

and so, the figure shows all the right directional angles for lines AB, B1, 12, 23, 34, 45.

Now. How to count directional angles.

Directional angles are calculated by the formula:

for the right angles:

α_n = α_n-1+180 –β_n

for left corners:

α_n = α_n-1–β_n +180

α_n-1 - Directional angle of the previous side

β_n - measured angle right along the way (for lines 12, 23, 34, 45, 51 - Average angle - 1 part of work table), (for lines AB - in your outline on the picture)

So you count the directional angles: