Page 114 - TB_6B

Learn how to find the sum of the interior angles of a polygons.

A quadrilateral, pentagon, and hexagon are divided into 2, 3, and
4 triangles. Therefore, the sum of the interior angles is equal to 180
multiplied by the number of triangles in each polygon.

180 2 180 3 180 4
(4 2) (5 2) (6 2)

(n 2) triangles can be made from a polygon with n number of sides.
So, the sum of the interior angles of a polygon with n number of sides is

180 (n 2).

1 . Find the sum of the interior angles of each polygon.

a. Octagon b. Decagon c. Dodecagon

27. Interior and Exterior Angles 103