$\alpha$  -  $\beta$  - 360°

 $\alpha$  + $\beta$  - 360°

 $-\alpha$ + $\beta$  + 360°

 $-\alpha$ -  $\beta$  + 360°

11 312"

10 282"

11 280"

11 282"

117°

118°

119°

116°

40

30

20

10