r i = a 1 2 ( 1 + 2 ) {\displaystyle r_{i}=a\ {\frac {1}{2}}(1+{\sqrt {2}})}
a = 2 r i ( 2 − 1 ) {\displaystyle a=2r_{i}\ ({\sqrt {2}}-1)}
r u = a 1 2 4 + 2 2 {\displaystyle r_{u}=a\ {\frac {1}{2}}{\sqrt {4+2{\sqrt {2}}}}}
r u = a 1 + 1 2 {\displaystyle r_{u}=a\ {\sqrt {1+{\frac {1}{\sqrt {2}}}}}}
a = r u 2 − 2 {\displaystyle a=r_{u}\ {\sqrt {2-{\sqrt {2}}}}}
d 1 = a 4 + 2 2 = 2 r u {\displaystyle d_{1}=a\ {\sqrt {4+2{\sqrt {2}}}}\ =\ 2r_{u}}
d 2 = a ( 1 + 2 ) = 2 r i {\displaystyle d_{2}=a\ (1+{\sqrt {2}})\ =\ 2r_{i}}
d 3 = a 2 + 2 = r u 2 {\displaystyle d_{3}=a\ {\sqrt {2+{\sqrt {2}}}}\ =\ r_{u}\,{\sqrt {2}}}
α = 360 ∘ 8 = 45 ∘ {\displaystyle \alpha ={\frac {360^{\circ }}{8}}=45^{\circ }}
| δ = 180 ∘ − α = 135 ∘ {\displaystyle \delta =180^{\circ }-\alpha =135^{\circ }}
cos δ = − 1 2 {\displaystyle \cos \delta ={\frac {-1}{\sqrt {2}}}}
A = a 2 ( 2 + 2 2 ) {\displaystyle A=a^{2}\ (2+2{\sqrt {2}})}
A = r u 2 2 2 {\displaystyle A=r_{u}^{2}\ 2{\sqrt {2}}}
