The sum of the interior angle of a regular polygon is 1800o. Calculate the size of one exterior angle of the polygon
-
A.
30o -
B.
24o -
C.
18o -
D.
12o
Correct Answer: Option A
Explanation
Sum of interior ∠s = 1800o
∴(n – 2) 180o = 1800o
180n -360o = 1800o
180n = 1800o + 360o
180n = 2160o
n = 2160o/180o
n = 12 sides
Each exterior ∠ = 360o/n
= 360o/12
= 30o