For this case we have from the first quadrant that:
[tex]70 + A1 = 90[/tex]
Clearing angle 1:
[tex]A1 = 90-70[/tex]
[tex]A1 = 20\ degrees[/tex]
Ahors, the angle A3 of the third quadrant measures 70 degrees, it is observed that it is opposed by the vertex at the angle of 70 degrees of the first quadrant. So:
[tex]A3-A1 = 70-20 = 50[/tex]
Answer:
Option B
