Английская Википедия:Elongated pentagonal orthobirotunda
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Шаблон:Short description Шаблон:Infobox polyhedron
In geometry, the elongated pentagonal orthobirotunda is one of the Johnson solids (Шаблон:Math). Its Conway polyhedron notation is at5jP5. As the name suggests, it can be constructed by elongating a pentagonal orthobirotunda (Шаблон:Math) by inserting a decagonal prism between its congruent halves. Rotating one of the pentagonal rotundae (Шаблон:Math) through 36 degrees before inserting the prism yields the elongated pentagonal gyrobirotunda (Шаблон:Math).
Formulae
The following formulae for volume and surface area can be used if all faces are regular, with edge length a:[1]
- <math>V=\frac{1}{6}\left(45+17\sqrt{5}+15\sqrt{5+2\sqrt{5}}\right)a^3\approx21.5297...a^3</math>
- <math>A=\left(10+\sqrt{30\left(10+3\sqrt{5}+\sqrt{75+30\sqrt{5}}\right)}\right)a^2\approx39.306...a^2</math>
References
External links
Шаблон:Johnson solids navigator Шаблон:Polyhedron-stub
- ↑ Stephen Wolfram, "Elongated pentagonal orthobirotunda" from Wolfram Alpha. Retrieved July 26, 2010.