Octahedron (EntityTopic, 14)
From Hi.gher. Space
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- | {{Shape|Octahedron|http://img473.imageshack.us/img473/3851/octahedron3vn.png|3|8, 12, 6|0|{[[Triangle|3,]]4}, r{3,3}, sr{2,3} | + | {{Shape|Octahedron|http://img473.imageshack.us/img473/3851/octahedron3vn.png|3|8, 12, 6|0|{[[Triangle|3,]]4}, r{3,3}, sr{2,3} or s{3}h{ }|<nowiki>4 | 2 3, 2 | 3 3, or | 2 2 3 |</nowiki>|<xyz> or {G3^4}|N/A|[[Square]], edge 1|Oct|[[Cube]]|N/A|<xyz>|9|none|<sup>1</sup>⁄<sub>π</sub> ≈ 0.3183|''Unknown''|[[Triangle|3]]<sup>4</sup>|SSC}} |
== Equations == | == Equations == | ||
*Variables: | *Variables: |
Revision as of 07:58, 23 September 2007
Equations
- Variables:
l ⇒ length of edges of the octahedron
- The hypervolumes of a octahedron are given by:
total edge length = 12l
surface area = 2sqrt(3)l2
volume = sqrt(3)-1l3
- The planar cross-sections (n) of an octahedron are:
[!x, !y, !z] ⇒ square of side (sqrt(2)-1l-abs(n)) rotated by 45°
Segmentation
The octahedron of side √2 may be segmented into 8× irregular tetrahedron with sides 3×1, 3×22-1.
Notable Trishapes | |
Regular: | tetrahedron • cube • octahedron • dodecahedron • icosahedron |
Direct truncates: | tetrahedral truncate • cubic truncate • octahedral truncate • dodecahedral truncate • icosahedral truncate |
Mesotruncates: | stauromesohedron • stauroperihedron • stauropantohedron • rhodomesohedron • rhodoperihedron • rhodopantohedron |
Snubs: | snub staurohedron • snub rhodohedron |
Curved: | sphere • torus • cylinder • cone • frustum • crind |
8. <[xy]z> Wide octahedron | 9. <xyz> Octahedron | 10. <(xy)z> Bicone |
List of bracketopes |