The difference between the exterior and interior angles

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The difference between the exterior and interior angles at a vertex of a regular polygon is 150°. The number of sides of the polygon is

Let the number of sides of polygon be n. Then
According to question ,
Difference = Interior angle of a polygon - Exterior angle of a polygon = 150

∴	(2n - 4)	× 90° -	360°	= 150
	n		n

⇒	(2n - 4) × 3	-	12	= 5
	n		n

⇒	6n - 12 - 12	= 5
	n

⇒ 6n – 24 = 5n
⇒ n = 24