The sum of the interior angle of a regular poly... - JAMB Mathematics 2005 Question

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