Each central angle of a regular 9 sided polygon: 360/9 = 40 degrees
30
36
A regular polygon having an interior angle measure of 168o has 30 sides and is called a triacontagon.
If the measure of an interior angle of a regular polygon is 140o, the polygon is a nonagon (sometimes called an ennagon) having 9 sides.
Each central angle is (360) divided by (number of sides in the polygon).
6
36
To calculate the measure of a central angle of a regular nine-sided polygon, divide 360 degrees by the number of sides. In this case, divide 360 by 9. The measure of the central angle of a regular nine-sided polygon is 40 degrees.
Each central angle of a regular 9 sided polygon: 360/9 = 40 degrees
The central angle of a n-sided regular polygon = 360 degrees / n. Hence, the central angle of a 15-sided regular polygon = 360 degrees / 15 = 24 degrees ============================
30
36
40
30o
360 degrees
20