The area of a polygon equals area = circumradius² * number of sides * sin (360 / # of sides) / 2 area = 77² * 20 * sin (360 / 20) / 2 area = 77² * 20 * sin (18) / 2 area = 118,580 * 0.30902 / 2 area =
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36,643.59
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/ 2 area =
18,321.8 square millimeters
