![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
The regular polygon has 18 sides.
\Sum of the measures of exterior angles of a regular polygon is 360.
\![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=336892a2e2a6b3095bf16fa5b4e73496.png\")
(n is the measure of the exterior angle)
![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=0449cfdcb2c13138b01f6209b479cb9e.png\")
(Divide each side by 18)
The measure of each exterior angle of the polygon is 20.![\"\"](\"/userfiles/image/steps_images/step2.JPG\")
Since each exterior angle and its corresponding interior angle form a linear pair,
\the measure of the interior angle is ![\"\"](\"/test/fckeditor/editor/plugins/fckeditor_wiris/integration/showimage.php?formula=1588077d028cc9e1e408cf22e6aaa9e2.png\")
.![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
The measure of an exterior angle of the polygon is 20.
\The measure of an interior angle of the polygon is 160.