Puas yog tetrahedron Ib txwm polyhedron?
Puas yog tetrahedron Ib txwm polyhedron?

Video: Puas yog tetrahedron Ib txwm polyhedron?

Video: Puas yog tetrahedron Ib txwm polyhedron?
Video: Da Vang - Puas Yog Nyuab2 Koj (nkauj tawm tshiab 2021) 2024, Kaum ib hlis
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A tetrahedron yog a polyhedron nrog 4 daim duab peb sab raws li nws lub ntsej muag. Tsis tu ncua polyhedra yog uniform thiab muaj ntsej muag ntawm txhua yam ntawm ib hom congruent tsis tu ncua polygon. Muaj tsib tsis tu ncua polyhedra . Cov tsis tu ncua polyhedra yog ib feem tseem ceeb ntawm Plato lub ntuj lub tswv yim, thiab yog li tau los hu ua Platonic Solids.

Yog li ntawd, uas yog ib txwm polyhedron?

A tsis tu ncua polyhedron yog a polyhedron uas pab pawg symmetry ua transitively ntawm nws cov chij. A tsis tu ncua polyhedron yog symmetrical heev, yog tag nrho ntawm ntug-transitive, vertex-transitive thiab ntsej muag-transitive. Tsis tas li ntawd, muaj tsib tsis tu ncua compounds ntawm cov tsis tu ncua polyhedra.

Tsis tas li ntawd, vim li cas tetrahedron yog polyhedron? Zoo li tag nrho cov pyramids, lub tetrahedron yog a polyhedron (piv txwv li peb-dimensional geometrical duab nrog lub ntsej muag tiaj tus thiab cov npoo ncaj). Nws muaj plaub (4) ntsej muag (lo lus tetra muaj nws keeb kwm hauv cov lus Greek, thiab txhais tau tias plaub), rau (6) ntug, thiab plaub (4) vertices.

Tsis tas li ntawd, puas yog daim duab peb sab prism ib txwm polyhedron?

Hauv geometry, a daim duab peb sab prism yog peb sab prism ; nws yog a polyhedron ua a daim duab peb sab lub hauv paus, ib daim ntawv txhais lus, thiab 3 lub ntsej muag koom nrog sab nraud. Ib txoj cai daim duab peb sab prism muaj cov duab plaub sab, txwv tsis pub nws yog oblique. Tag nrho cov kab sib txuas mus rau lub hauv paus ntsej muag yog tib yam daim duab peb sab.

Dab tsi yog 20 sided polyhedron hu ua?

Lo lus tsis tu ncua qhia tias lub ntsej muag thiab cov duab vertex yog cov polygons tsis tu ncua, piv txwv li, kom paub qhov txawv ntawm cov dodecahedron tsis tu ncua (uas yog Platonic khoom) los ntawm ntau dodecahedra. Ib yam li ntawd, icosi-, lub ntsiab lus 20 , yog siv nyob rau hauv 20 - sab icosahedron, illustrated ntawm txoj cai.

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