Hauv kev tshaj tawm no, peb yuav xav txog cov ntsiab lus, cov ntsiab lus tseem ceeb, hom thiab cov kev xaiv ua tau rau seem ntawm lub pyramid. Cov ntaub ntawv nthuav tawm yog nrog rau cov duab kos duab kom pom kev zoo dua.
Pyramid txhais
Pyramid yog ib daim duab geometric hauv qhov chaw; ib lub polyhedron uas muaj lub hauv paus thiab sab ntsej muag (nrog ib qho vertex), tus naj npawb ntawm cov uas nyob ntawm tus naj npawb ntawm cov ces kaum ntawm lub hauv paus.
Nco ntsoov: pyramid yog ib rooj plaub tshwj xeeb.
pyramid ntsiab
Rau daim duab saum toj no:
- Base (quadrangle ABCD) - lub ntsej muag ntawm daim duab uas yog polyhedron. Nws tsis muaj lub sab saum toj.
- Sab saum toj ntawm lub pyramid (point E) yog lub ntsiab lus ntawm txhua sab ntsej muag.
- Sab ntsej muag yog triangles uas converge ntawm ib tug vertex. Hauv peb qhov xwm txheej, qhov no yog: Cov xwm txheej dav dav ntawm kev yuav khoom, AED, BEC и CED.
- Sab tav - sab ntawm sab ntsej muag, tshwj tsis yog cov uas koom nrog lub hauv paus. Cov. qhov no yog AE, BE, CE и DE.
- Pyramid Qhov siab (EF or h) - ib qho perpendicular poob los ntawm sab saum toj ntawm lub pyramid mus rau nws lub hauv paus.
- Sab ntsej muag qhov siab (EM) - qhov siab ntawm daim duab peb sab, uas yog sab ntsej muag ntawm daim duab. Hauv ib lub pyramid li niaj zaus hu ua apothematic.
- Qhov chaw ntawm lub pyramid yog thaj tsam ntawm lub hauv paus thiab tag nrho nws sab ntsej muag. Cov qauv rau kev nrhiav (qhov tseeb daim duab), nrog rau cov pyramids, tau nthuav tawm hauv cov ntawv sib cais.
Pyramid kev loj hlob - daim duab tau txais los ntawm "txiav" lub pyramid, piv txwv li thaum tag nrho nws lub ntsej muag yog raws li nyob rau hauv lub dav hlau ntawm ib tug ntawm lawv. Rau ib txwm quadrangular pyramid, txoj kev loj hlob nyob rau hauv lub dav hlau ntawm lub hauv paus yog raws li nram no.
Nco ntsoov: nthuav tawm nyob rau hauv ib qho kev tshaj tawm cais.
Sectional views ntawm lub pyramid
1. Diagonal seem - lub dav hlau txiav hla mus rau sab saum toj ntawm daim duab thiab kab pheeb ces kaum ntawm lub hauv paus. Lub pyramid quadrangular muaj ob ntu (ib qho rau txhua kab pheeb ces kaum):
2. Yog hais tias lub dav hlau txiav yog sib npaug rau lub hauv paus ntawm lub pyramid, nws muab faib ua ob daim duab: lub pyramid zoo sib xws (suav los ntawm sab saum toj) thiab lub hauv paus pyramid (suav los ntawm lub hauv paus). Cov seem yog lub hauv paus zoo li polygon.
Hauv daim duab no:
- pyramids EABCD и EA1B1C1D1 zoo sib xws;
- quadrangles ABCD и A1B1C1D1 kuj zoo ib yam.
Nco ntsoov: Muaj lwm hom kev txiav, tab sis lawv tsis yog li ntawd.
Hom pyramids
- Tsis tu ncua pyramid - lub hauv paus ntawm daim duab yog ib tug tsis tu ncua polygon, thiab nws vertex yog npaj rau hauv nruab nrab ntawm lub hauv paus. Nws tuaj yeem yog daim duab peb sab, plaub fab (daim duab hauv qab), pentagonal, hexagonal, thiab lwm yam.
- Pyramid nrog ib sab ntug perpendicular mus rau lub hauv paus - Ib qho ntawm cov npoo ntawm daim duab yog nyob ntawm lub kaum sab xis rau lub dav hlau ntawm lub hauv paus. Hauv qhov no, ntug no yog qhov siab ntawm lub pyramid.
- Pyramid txiav - ib feem ntawm lub pyramid uas tseem nyob nruab nrab ntawm nws lub hauv paus thiab lub dav hlau txiav thaum uas tig mus rau lub hauv paus no.
- Tetrahedron - Qhov no yog daim duab peb sab pyramid, lub ntsej muag uas yog 4 daim duab peb sab, txhua tus tuaj yeem coj los ua lub hauv paus. Yog muaj tseeb (raws li hauv daim duab hauv qab no) - yog tias tag nrho cov npoo sib npaug, piv txwv li txhua lub ntsej muag yog daim duab peb sab sib npaug.
