m∠1 = _°
a) 140
b) 160
c) 80

Answer:
Option c [tex]80\°[/tex]
Step-by-step explanation:
we know that
The measurement of the external angle is the semi-difference of the arcs which comprises
so
in this problem
[tex]m<1=\frac{1}{2}(220\°-60\°)=80\°[/tex]