Tetrahedron hauv Greek txhais tau tias "tetrahedron". Daim duab geometric no muaj plaub lub ntsej muag, plaub ntsug thiab rau ntawm ntug. Cov npoo yog daim duab peb sab. Qhov tseeb, tetrahedron yog daim duab peb sab pyramid. Thawj qhov hais txog polyhedra tshwm sim ntev ua ntej Plato muaj.
Hnub no peb yuav tham txog cov ntsiab lus thiab cov khoom ntawm tetrahedron, thiab tseem kawm cov qauv los nrhiav thaj chaw, ntim thiab lwm yam tsis muaj ntawm cov ntsiab lus no.
Cov ntsiab lus ntawm tetrahedron
Cov kab ntu, tso tawm los ntawm ib qho vertex ntawm tetrahedron thiab qis mus rau qhov kev sib tshuam ntawm qhov nruab nrab ntawm lub ntsej muag sab nraud, hu ua qhov nruab nrab.
Qhov siab ntawm polygon yog ib ntu ib txwm poob los ntawm qhov rov qab vertex.
Ib tug bimedian yog ib ntu txuas cov chaw ntawm kev hla ntug.
Txoj khoom ntawm tetrahedron
1) Cov dav hlau sib luag uas dhau los ntawm ob lub npoo npoo tsim ib lub thawv uas tau hla.
2) Ib qho khoom tshwj xeeb ntawm tetrahedron yog qhov ntawdcov medians thiab bimedians ntawm daim duab sib ntsib ntawm tib lub ntsiab lus. Nws yog ib qho tseem ceeb uas tom kawg faib cov nruab nrab hauv qhov sib piv ntawm 3: 1, thiab bimedians - hauv ib nrab.
3) Lub dav hlau faib ib lub tetrahedron rau hauv ob feem ntawm qhov sib npaug yog tias nws hla nruab nrab ntawm ob txoj kab hla.
Types of tetrahedron
Txoj kev sib txawv ntawm daim duab yog dav heev. Ib tetrahedron tuaj yeem yog:
- raug, uas yog, ntawm lub hauv paus ntawm daim duab peb sab sib npaug;
- equihedral, uas txhua lub ntsej muag yog tib yam ntev;
- orthocentric thaum qhov siab muaj qhov sib txuam ntawm kev sib tshuam;
- duab plaub yog tias cov kaum tiaj tiaj ntawm sab saum toj yog qhov qub;
- proportionate, tag nrho ob qhov siab yog sib npaug;
- wireframe yog tias muaj tus kheej uas kov cov npoo;
- incentric, uas yog, ntu poob ntawm lub vertex mus rau qhov chaw ntawm lub voj voog inscribed ntawm lub ntsej muag opposite muaj ib qho kev sib tshuam taw tes; lub ntsiab lus no hu ua centroid ntawm lub tetrahedron.
Cia peb nyob ntawm lub tetrahedron li niaj zaus, cov khoom ntawm cov uas xyaum zoo ib yam.
Raws li lub npe, koj tuaj yeem nkag siab tias nws hu ua li ntawd vim lub ntsej muag yog daim duab peb sab. Tag nrho cov npoo ntawm daim duab no yog congruent nyob rau hauv ntev, thiab lub ntsej muag yog congruent nyob rau hauv cheeb tsam. Ib qho tetrahedron li niaj zaus yog ib qho ntawm tsib yam zoo sib xws polyhedra.
Tetrahedron formulas
Qhov siab ntawm tetrahedron yog sib npaug rau cov khoom ntawm cov hauv paus hniav ntawm 2/3 thiab qhov ntev ntawm ntug.
Lub ntim ntawm ib lub tetrahedron pom zoo ib yam li qhov ntim ntawm lub pyramid: lub hauv paus square ntawm 2 muab faib los ntawm 12 thiab muab faib los ntawm qhov ntev ntawm ntug hauv lub voos xwmfab.
Lwm cov qauv rau kev suav thaj tsam thiab lub voj voog ntawm lub voj voog tau nthuav tawm saum toj no.
