txheem
Rhombuses yog ib daim duab geometric; parallelogram nrog 4 sab sib npaug.
Cov qauv hauv cheeb tsam
Sab ntev thiab qhov siab
Lub cheeb tsam ntawm lub rhombus (S) yog sib npaug rau cov khoom ntawm qhov ntev ntawm nws sab thiab qhov siab kos rau nws:
S = a ⋅ h
Los ntawm sab ntev thiab lub kaum sab xis
Lub cheeb tsam ntawm lub rhombus yog sib npaug rau cov khoom ntawm lub square ntawm qhov ntev ntawm nws sab thiab lub sine ntawm lub kaum sab xis ntawm ob sab:
S = ib 2 ⋅ tsis muaj α
Los ntawm qhov ntev ntawm cov diagonals
Lub cheeb tsam ntawm lub rhombus yog ib nrab ntawm cov khoom ntawm nws cov kab pheeb ces kaum.
S = Cov 1/2 ⋅ d1 ⋅ d2
Piv txwv ntawm cov dej num
Txoj Haujlwm 1
Nrhiav thaj tsam ntawm lub rhombus yog tias qhov ntev ntawm nws sab yog 10 cm thiab qhov siab kos rau nws yog 8 cm.
Kev txiav txim siab:
Peb siv thawj cov qauv uas tau tham saum toj no: S u10d 8 cm ⋅ 80 cm uXNUMXd XNUMX cm2.
Txoj Haujlwm 2
Nrhiav thaj tsam ntawm lub rhombus uas nws sab yog 6 cm thiab nws lub kaum sab xis yog 30 °.
Kev txiav txim siab:
Peb siv cov qauv thib ob, uas siv cov khoom uas paub los ntawm cov xwm txheej ntawm kev teeb tsa: S = (6 cm)2 ⋅ sin 30° = 36 cm2 ⋅ 1/2 = 18 cm2.
Txoj Haujlwm 3
Nrhiav thaj tsam ntawm lub rhombus yog tias nws cov kab pheeb ces kaum yog 4 thiab 8 cm, feem.
Kev txiav txim siab:
Cia peb siv tus qauv thib peb, uas siv qhov ntev ntawm kab pheeb ces kaum: S = 1/2 ⋅ 4 cm ⋅ 8 cm = 16 cm2.