A378208 Decimal expansion of the dihedral angle, in radians, between any two adjacent faces in a triakis tetrahedron.

2, 2, 6, 0, 5, 7, 1, 3, 2, 7, 5, 8, 0, 3, 9, 6, 2, 7, 9, 3, 4, 1, 3, 5, 7, 8, 1, 1, 6, 0, 8, 6, 5, 5, 9, 6, 5, 5, 5, 5, 2, 8, 4, 1, 8, 0, 5, 3, 8, 1, 2, 6, 2, 4, 1, 4, 3, 2, 0, 8, 6, 9, 2, 9, 0, 2, 4, 3, 4, 2, 7, 6, 4, 6, 3, 1, 4, 2, 4, 7, 7, 2, 1, 0, 8, 6, 3, 9, 2, 3

Offset: 1

Author

Paolo Xausa, Nov 21 2024

Keywords

• nonn
• cons
• easy

Comments

The triakis tetrahedron is the dual polyhedron of the truncated tetrahedron.

Examples

			2.2605713275803962793413578116086559655552841805381...
		

Links

• Wikipedia, Triakis tetrahedron.
• Index entries for transcendental numbers.

Crossrefs

Cf. A378204 (surface area), A378205 (volume), A378206 (inradius), A378207 (midradius).

Cf. A137914 and A156546 (dihedral angles of a truncated tetrahedron).

Programs

Mathematica

First[RealDigits[ArcCos[-7/11], 10, 100]] (* or *)
First[RealDigits[First[PolyhedronData["TriakisTetrahedron", "DihedralAngles"]], 10, 100]]

Formula

Equals arccos(-7/11).