Answer:
19. The exterior angles add up to 360 degrees, (as do all polygons).
20. See below. (Answers in bold).
Explanation:
The exterior angles of all polygons add up to 360 degrees.
a. Pentagon : Exterior angle = 360 / 5 = 72 degrees.
So an interior angle measures 180 - 72 = 108 degrees.
b. 16-gon:- Exterior angle = 360 / 16 = 22.5 degrees.
Interior angle = 180 - 22.5 = 157.5 degrees.
c. Dodecagon has 12 sides so exterior angle = 360 / 12 = 30 degrees.
Interior angle = 150 degrees.