Formulary: Maths - Geometry - Octagon

Octagon

Definitions:

  • a: Edge Length
  • U: Perimeter
  • A: Area
U a

Perimeter of an Octagon

The perimeter U is the length of all 8 sides.

\( {\color{blue} {U}} = 8 \times {\color{red} {a} } \)
U = Perimeter
a = Edge Length

\( {\color{red} {a} } = \frac{\color{blue} {U}}{8} \)
a = Edge Length
U = Perimeter


A a

Area of an Octagon

The region inside an ocatagon.

\( {\color{OliveGreen} {A}} = 2 \times \left( 1 + \sqrt{2} \right) \times {\color{red} {a} }^{2} \)
A = Area
a = Edge Length

\( {\color{red} {a} } = \sqrt{ \frac{\color{OliveGreen} {A}}{ 2 \times \left( 1 + \sqrt{2} \right) } } \)
a = Edge Length
A = Area