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The interior angle of a regular polygon is more by 144 degree than its exterior angle. Find the number of sides of regular polygon.
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You are given
Int + Ext = 180 (1)
Int - Ext = 144 (2) ("The interior angle of a regular polygon is more by 144degree than its exterior angle.")
Subtract equations (2) from equation (1) to get
2*Ext = 180 - 144 = 36 degrees ====> Ext = = 18 degrees.
Now use the fact that the sum of all exterior angles of a polygon is equal to 360 degrees:
n*Ext = 360, which implies n = = 20.
ANSWER. The number of sides of the given regular polygon is 20.
Solved.