Classifications | Formulas

No. of Sides |
Kind of Polygon |
No. of Sides |
Kind of Polygon |

3 | Triangle | 7 | Heptagon |

4 | Quadrilateral | 8 | Octagon |

5 | Pentagon | 9 | Nonagon |

6 | Hexagon | 10 | Decagon |

Pentagon |
Hexagon |
Octagon |

Perimeter |
||

P=5R sqrt(10-2 sqrt[5])/2 | P=6R | P=8R sqrt(2-sqrt[2]) |

Area |
||

K=5a sqrt(4R^{2}-a^{2})/4 |
K=3a sqrt(4R^{2}-a^{2})/2 |
K=2a sqrt(4R^{2}-a^{2}) |

Perimeter: P

Area: K

Radius of circumscribed circle: R

Sides, all equal length: a