Pentagon Calculator
Results
Area
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Perimeter
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Apothem
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Circumradius
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Diagonal
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Interior Angle
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About Regular Pentagon
A regular pentagon is a five-sided polygon where all sides are equal in length and all angles are equal (108°).
Formulas
Area = (5/4) × s² × cot(π/5)
Perimeter = 5s
Apothem = s/(2 × tan(π/5))
Circumradius = s/(2 × sin(π/5))
Diagonal = s × (1 + √5)/2
Interior Angle = 108°
Where s is the side length.
Properties
- All sides are equal in length
- All interior angles are 108°
- All exterior angles are 72°
- Has 5 diagonals
- Can be inscribed in a circle
- Has 5 lines of symmetry