Question 1091456
Sum=(n-2)*180
exterior angle sum is always 360.
a.  (n-2)*180=360; n-2=2; n=4. A square.
b.  (n-2)*180=720; n-2=4; n=6. A hexagon.
c. (n-2)*180=1800; n-2=10; n=12. A dodecagon.