The sum of the interior angle of a regular polygon is 1800

^{o}. Calculate the size of one exterior angle of the polygon-
**A.**

30^{o} -
**B.**

24^{o} -
**C.**

18^{o} -
**D.**

12^{o}

##### Correct Answer: Option A

##### Explanation

Sum of interior ∠s = 1800^{o}

∴(n – 2) 180^{o} = 1800^{o}

180n -360^{o} = 1800^{o}

180n = 1800^{o} + 360^{o}

180n = 2160^{o}

n = 2160^{o}/180^{o}

n = 12 sides

Each exterior ∠ = 360^{o}/n

= 360^{o}/12

= 30^{o}