Area of a Pentagon Formula

A Pentagon is a five-sided polygon in geometry. It may be simple or self – intersecting in shape. The five angles present in the Pentagon are equal. A regular pentagon has all of the sides and angles are the same as each other. Pentagons can be regular or irregular and convex or concave. A regular pentagon is one with all equal sides and angles. Its interior angles are 108 degrees and its exterior angles are 72 degrees. An irregular pentagon is a shape that does not have equal sides and/or angles and therefore does not have specified angles. A convex pentagon is one whose vertices, or points, where the sides meet, is pointing outwards as opposed to a concave pentagon whose vertices point inwards. Imagine a collapsed roof of a house. Now, the Pentagon area is derived by multiplying side and apothem length with (5/2). To learn more about the area of a pentagon along with the details of apothem and other related details, check the linked article.

Area of a Pentagon Formula

Area Formula for a Pentagon

The Area of a Pentagon Formula is,

A = (5 ⁄ 2) × s × a


  • “s” is the side of the Pentagon and
  • “a” is the apothem length.

Example Questions Using Pentagon Area Formula

Question 1: Find the area of a pentagon of side 10 cm and apothem length 5 cm ? Solution: Given, s = 10 cm a = 5 cm Area of a pentagon = A = (5 ⁄ 2) × s × a = A = (5 ⁄ 2) × 10 × 5 cm2 = 125 cm2.

Practise This Question

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