AREA AND PERIMETER WORD PROBLEMS - onlinemath4all = 1/2(apothem)(perimeter of polygon) ----(1) In the above regular pentagon, apothem is 4 m. The perimeter of a regular polygon is = (No. of sides)(Length of each side) Therefore, the perimeter of the regular pentagon shown above is = 5(6) = 30 m. To find the area of the regular pentagon, substitute 4 for apothem and 30 for perimeter in the ...