Geometry

The sum of the interior angles of polygon is 1800. Find the number of sides in the polygon and, what do you call that polygon?

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  1. for n sides
    exterior angle = 360/n
    so interior angle = 180 - 360/n
    sum of interior angles = n(180 - 360/n)
    =180 n (1 - 2/n)
    so here
    1800 = 180 n (1 - 2/n)
    10 = n - 2
    n = 12 sides

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  2. duodecaon etc.:
    http://www.absorblearning.com/mathematics/demo/units/KCA008.html

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  3. duodecagon I mean

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  4. glooks

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