SOLUTION: what is the area of a decagon with a perimiter of 20 inches

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Question 454773: what is the area of a decagon with a perimiter of 20 inches
Answer by Gogonati(855) About Me  (Show Source):
You can put this solution on YOUR website!
If we consider the regular decagon, its area is given by the formula:
A=p%2Aa%2F2, where p is the perimeter and a the apotem ( Apotem is the line
segment from the center of decagon perpendicular to the side)
a=1%2Ftan18=3.08inches. and A=20%2A3.08%2F2=30.8 square inches.