ASAP please help I will give the brainliest ！

If it is an 18-gon with a perimeter of 72mm then each side equals 72 / 18 =
4 mm
Area of a polygon = (n * side^2) / (4 * tan (180 / n))
where "n" is the number of sides
Area = (18 * 4^2) / (4 * 0.17633)
Area = 18 * 4  / 0.17633
Area = 408.33 square millimeters

Source:
http://www.1728.org/polygon.htm