| Hemi-icosahedron | |
|---|---|
 decagonal Schlegel diagram | |
| Type | abstract regular polyhedron globally projective polyhedron |
| Faces | 10 triangles |
| Edges | 15 |
| Vertices | 6 |
| Euler char. | χ = 1 |
| Vertex configuration | 3.3.3.3.3 |
| Schläfli symbol | {3,5}/2 or {3,5}5 |
| Symmetry group | A5, order 60 |
| Dual polyhedron | hemi-dodecahedron |
| Properties | non-orientable |
In geometry, a hemi-icosahedron is an abstract regular polyhedron, containing half the faces of a regular icosahedron. It can be realized as a projective polyhedron (a tessellation of the real projective plane by 10 triangles), which can be visualized by constructing the projective plane as a hemisphere where opposite points along the boundary are connected and dividing the hemisphere into three equal parts.