There are 2 formulas for finding the area of a pentagon. The first only needs the side length; the second also uses the apothem.
When you only know the length of one side, use this formula:
If you also know the apothem, you can use either of these equivalent expressions:
Both expressions are equivalent and give the same result.
In a regular polygon like the pentagon, the apothem is the shortest distance from the center to any of its sides. The image below shows this clearly:
Click on any element to learn more.
