Pib pib ua stereometric hauv tsev kawm ntawv, tsis yog txhua tus tuaj yeem taw qhia lawv tus kheej hauv qhov chaw tam sim: nws tsis yog dav hlau. Qee lub sij hawm txawm tias cov lus nug yooj yim tshaj plaws tsis meej pem. Piv txwv li, lub thawv muaj pes tsawg lub ntsej muag? Qhov no tsis yooj yim heev los teb thawj zaug, vim tias feem ntau ntawm peb feem ntau yuav pib suav, xav txog ib daim duab hauv peb lub taub hau. Hauv tsab xov xwm no, peb yuav txheeb xyuas seb tus parallelepiped yog dab tsi, vim li cas nws thiaj hu ua qhov ntawd thiab muaj pes tsawg lub ntsej muag parallelepiped muaj. Koj yuav kawm tag nrho cov no thiab ntau ntxiv los ntawm kab lus no.
Ib lub thawv muaj pes tsawg lub ntsej muag thiab nws yog dab tsi
Raws li lub npe, peb tuaj yeem xaus tias muaj cov kab sib txuas. Yog li, ib qho parallelepiped yog ib daim duab peb sab, lossis zoo li, ib lub polyhedron uas muaj rau lub ntsej muag, txhua tus uas yog parallelogram.
Dab tsi yog parallelogram? Qhov no yog quadrilateralPlanimetry, nyob rau hauv uas opposite sab yog pairwise parallel thiab sib npaug. Ib tug parallelogram uas muaj tsawg kawg yog ib lub kaum sab xis (tus so yog cia li sib npaug rau 90 degrees) yog ib daim duab plaub. Yog tias tag nrho cov sab kuj sib npaug, thiab cov kaum sab xis yog, ces qhov no yog square.
Los ntawm lub ntsiab lus, peb nkag siab tias muaj pes tsawg lub ntsej muag ntawm parallelepiped muaj. Teb: muaj 6.
Thiab muaj pes tsawg lub ntsej muag ua lub duab plaub thiab square parallelepiped muaj? Qhov tseeb, txhua hom polyhedra no muaj tib lub ntsej muag: nyob rau hauv txhua rooj plaub muaj rau ntawm lawv.
Lub thawv duab plaub yog polyhedron uas nws lub ntsej muag tsis yog parallelograms, tab sis cov duab plaub.
Square muaj squares es tsis txhob parallelograms. Xws li ib tug parallelepiped yog hu ua lub voos xwmfab. Nws muaj qhov sib npaug ntawm txhua lub ntsej muag, npoo thiab kab pheeb ces kaum.
Zoo kawg
Yog li, hauv kab lus no peb saib seb lub thawv yog dab tsi, nws yog dab tsi thiab muaj pes tsawg lub ntsej muag lub thawv muaj. Thiab yog dab tsi ntau yam.
Geometry yog ib qho kev tshawb fawb tseeb thiab nthuav dav uas tsim nyog kawm, vim tias nws yuav los ua ke hauv lub neej yog tias koj xav tau tsim ib yam dab tsi. Txhob tub nkeeg, kawm yam tshiab!
