Answer:
m = 54
Step-by-step explanation:
The secant- secant angle 20° is half the difference of the intercepted arcs, that is
(160 - 2m - 12) = 20° ( multiply both sides by 2 to clear the fraction )
- 2m + 148 = 40° ( subtract 148 from both sides )
- 2m = - 108 ( divide both sides by - 2 )
m = 54