Inkreisradius
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)}
Umkreisradius
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}}}}}
