Octagram calculator and formula

This function calculates various parameters of an octagram.

To perform the calculation, select the property you know from the pull down menu and enter its value. Then click the 'Calculate' button.

Octagram calculator

Input

Decimal places

Results

Octagon edge a

Spike length b

Diagonal d

Chord length l

Perimeter P

Area A

Formulas for octagrams

Octagon edge length

\(\displaystyle a = (\sqrt{2} - 1) · l\;\;\; ≈0.4142·l\)

Spike length

\(\displaystyle b=\frac{2-\sqrt{2}}{2} · l\;\;\; ≈0.2929·l\)

Diagonal

\(\displaystyle d=\sqrt{4+2·\sqrt{2}} · a\;\;\; ≈2.613·a\)

Chord length

\(\displaystyle l=a+2 ·b\)

Area

\(\displaystyle A= (6· \sqrt{2} - 8) · l^2 \;\;\; ≈0.4853· l^2\)

Perimeter

\(\displaystyle P= 16·b\)