OFFSET
0,1
COMMENTS
Icosahedron: A three-dimensional figure with 20 equilateral triangle faces, 12 vertices, and 30 edges.
LINKS
FORMULA
Sqrt(75 + 30*sqrt(5))/15.
EXAMPLE
0.794654472291766122955530928327594042026590588309264801754955775008438...
MATHEMATICA
R=1; RealDigits[N[(Sqrt[75+30*Sqrt[5]]/15)*R, 175]]
PROG
(PARI) polrootsreal(45*x^4-30*x^2+1)[4] \\ Charles R Greathouse IV, Sep 02 2024
(PARI) sqrt(6/sqrt(5)+3)/3 \\ Charles R Greathouse IV, Sep 02 2024
CROSSREFS
KEYWORD
AUTHOR
Vladimir Joseph Stephan Orlovsky, Jul 09 2010
EXTENSIONS
Offset corrected, keyword:cons added by R. J. Mathar, Jul 11 2010
STATUS
approved