Find the area of each regular polygon.

12. 18gon with perimeter 72mm.

A regular polygon is equilateral (it has equal sides) and equiangular (it has equal angles).The area of a regular polygon is given by the formula below.

area = (½)(apothem)(perimeter)
area = 1/2 a (72)
area = 36a

Therefore, the area of an 18gon would be 36a where a is the apothem. Hope this answers the question. Have a nice day.