<PRE><B>Question 974592</B>
A regular pentagon with sides of length 4 is inscribed in a circle. Find the area of the Pentagon 
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{{{Area = ns^2*cot(180/n)/4}}} n = # of sides, s = side length (of all regular polygons)
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{{{Area = 5*16*cot(36)/4 = 20cot(36)}}}
Area =~ 27.528 sq units
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I&#39;m not a proponent of memorizing formulas as there are too many of them.
I know this one, tho.
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The circle is not relevant.</PRE>