Question 1031210
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A polygon of n sides has a half its interior angles equals to 150 degrees.while the rest of are equal to 170 degrees each. 
Find the number of sides of the polygon 
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18-gon.

18 sides and 18 vertices.

9 angles by 150° and 9 angles by 170°.


9*150° + 9*170° = 2880°.

From the other side,  (18-2)*180° = 2880°.
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