Formulary : Maths - Geometry

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

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