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Pentagon Area Calculator
All math tools
Calculate the area and perimeter of a regular pentagon.
Input Dimensions
Side length (s)
Pentagon Dimensions
Area (A)
172.0477
Perimeter (P)
50.0000
Apothem (a)
6.8819
Circumradius (R)
8.5065
About this calculator
What is a Regular Pentagon?
A regular pentagon is a five-sided polygon with all sides and interior angles equal. Each interior angle of a regular pentagon is 108 degrees.
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Pro Tips
The perimeter is simply 5 times the side length.
The area can also be expressed as (1/2) * perimeter * apothem.
The golden ratio (φ ≈ 1.618) is deeply related to the geometry of a pentagon.
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Fun Facts
"The Pentagon in Washington D.C. is one of the world's largest office buildings and is famous for its shape."
"Pentagonal symmetry is rare in inanimate minerals but common in living organisms like starfish."
Formula: Area = (1/4) * √(5(5 + 2√5)) * s²
