Ib lub duab plaub fab yog lub npe rau ib yam khoom uas muaj 6 sab uas txhua tus paub zoo heev - ib lub xwmfab. Xav txog ib lub cib los yog lub thawv rau khoom, uas yog ib qho piv txwv zoo tshaj plaws ntawm cov duab plaub fab. Qhov chaw saum npoo av yog qhov sib npaug ntawm thaj chaw saum npoo av ntawm ib yam khoom. "Kuv xav tau ntawv ntau npaum li cas los qhwv lub thawv ntawv no?" suab yooj yim dua, tab sis nws kuj yog teeb meem ntawm lej.
Kauj ruam
Ntu 1 ntawm 2: Nrhiav Qhov Chaw Nto
Kauj Ruam 1. Sau daim ntawv ntev, dav, thiab qhov siab
Txhua lub duab plaub prism muaj qhov ntev, dav, thiab qhov siab. Kos tus prism, thiab sau cov cim p, l, thiab t ib sab ntawm peb sab sib txawv ntawm qhov sawv.
- Yog tias koj tsis paub meej tias sab twg rau daim ntawv lo, xaiv ib qho twg. Sau peb kab uas tau ntsib ntawm qhov chaw ntawd.
- Piv txwv: Ib lub thawv muaj lub hauv paus 3 meters thiab 4 meters ntev thiab sawv siab 5 meters. Sab ntev ntawm lub hauv paus yog 4 meters, yog li p = 4, l = 3, thiab t = 5.
Kauj Ruam 2. Saib rau ntawm rau sab ntawm qhov prism
Txhawm rau npog tag nrho cov npoo loj, koj yuav tsum pleev xim rau rau sab sib txawv. Xav txog ib lub sijhawm - lossis nrhiav lub thawv ntim khoom noj thiab pom nws tus kheej:
- Muaj qhov nce thiab nqis. Ob leeg yog qhov loj me.
- Muaj sab xub ntiag thiab nraub qaum. Ob leeg yog qhov loj me.
- Muaj sab laug thiab sab xis. Ob leeg yog qhov loj me.
- Yog tias koj muaj teeb meem xav txog nws, txiav ib lub xwmfab raws cov ntug thiab kis nws tawm.
Kauj Ruam 3. Nrhiav thaj tsam ntawm sab hauv qab
Txhawm rau pib, cia nrhiav thaj tsam ntawm ib sab: hauv qab. Sab no yog duab plaub, zoo li txhua sab. Ib sab ntawm lub duab plaub tau sau lo lus ntev thiab lwm sab yog daim ntawv lo dav. Txhawm rau nrhiav thaj tsam ntawm ib lub duab plaub, tsuas yog muab ob sab los ua ke. Cheeb Tsam (sab hauv qab) = ntev lub sij hawm dav = pl.
Rov qab los rau peb qhov piv txwv, thaj tsam ntawm sab hauv qab yog 4 metres x 3 meters = 12 meters sib npaug
Kauj Ruam 4. Nrhiav thaj tsam ntawm sab saum toj
Tos - peb twb paub lawm tias sab saum toj thiab hauv qab yog qhov loj ib yam. Sab saum toj kuj yuav tsum muaj thaj chaw pl.
Hauv peb qhov piv txwv, thaj tsam saum toj kawg nkaus kuj yog 12 square metres
Kauj Ruam 5. Nrhiav thaj tsam ntawm sab xub ntiag thiab sab nraub qaum
Rov qab mus rau koj daim duab thiab saib rau sab xub ntiag: sab nrog ib daim ntawv sau dav dav thiab ib sab ntug sau npe qhov siab. Pem hauv ntej cheeb tsam = dav dav qhov siab = lt ua. Lub cheeb tsam ntawm sab nraub qaum kuj yog lt ua.
Hauv peb qhov piv txwv, l = 3 meters thiab t = 5 meters, yog li thaj tsam ntawm sab xub ntiag yog 3 metres x 5 meters = 15 meters sib npaug. Thaj tsam ntawm sab nraub qaum kuj yog 15 square metres
Kauj Ruam 6. Nrhiav thaj tsam ntawm sab laug thiab sab xis
Peb tsuas muaj ob sab sab laug, ob qho tib si yog qhov loj me. Ib sab ntug yog qhov ntev ntawm prism, thiab lwm ntug yog qhov siab ntawm prism. Cheeb tsam ntawm sab laug yog pt xab thiab thaj tsam ntawm sab xis kuj yog pt xab.
Hauv peb qhov piv txwv, p = 4 meters thiab t = 5 meters, yog li thaj tsam ntawm sab laug = 4 metres x 5 meters = 20 meters sib npaug. Thaj tsam ntawm sab xis tseem yog 20 square metres
Kauj Ruam 7. Ntxiv rau rau thaj tsam
Tam sim no, koj tau pom thaj tsam ntawm rau sab. Ntxiv cov cheeb tsam kom tau txais tag nrho thaj tsam ntawm daim duab: pl + pl + lt + lt + pt + pt. Koj tuaj yeem siv cov mis no rau ib qho duab plaub prism, thiab koj yuav ib txwm tau txais thaj chaw.
Txhawm rau ua kom tiav peb qhov piv txwv, tsuas yog ntxiv txhua tus lej xiav saum toj no: 12 + 12 + 15 + 15 + 20 + 20 = 94 square metres
Ntu 2 ntawm 2: Yooj Yim Cov Qauv
Kauj Ruam 1. Yooj yim rau cov mis
Tam sim no koj paub txaus txog yuav ua li cas thiaj pom thaj tsam ntawm ib qho duab plaub prism. Koj tuaj yeem ua nws sai dua yog tias koj tau kawm qee qhov lej lej yooj yim. Pib nrog peb qhov kev ua zauv saum toj no: Thaj tsam ntawm ib lub duab plaub prism = pl + pl + lt + lt + pt + pt. Yog tias peb muab tag nrho cov nqe lus qub, peb tau txais:
Thaj tsam ntawm cov duab plaub fab = 2pl + 2lt + 2pt
Kauj Ruam 2. Txiav tawm tus lej thib ob
Yog tias koj paub yuav ua li cas ua lej hauv algebra, koj tuaj yeem yooj yim cov qauv:
Thaj tsam ntawm Rectangular Prism = 2pl + 2lt + 2pt = 2 (pl + lt + pt).
Kauj Ruam 3. Ntsuas cov mis hauv qhov piv txwv
Cia peb rov qab mus rau peb lub npov piv txwv, nrog qhov ntev ntawm 4, dav ntawm 3, thiab qhov siab ntawm 5. Txuas cov lej no rau hauv tus lej:
Luas = 2 (pl + lt + pt) = 2 x (pl + lt + pt) = 2 x (4x3 + 3x5 + 4x5) = 2 x (12 + 15 + 20) = 2 x (47) = 94 square meters. Nov yog tib lo lus teb, uas peb tau txais ua ntej lawm. Thaum koj xyaum ua cov zauv no, cov mis no yog txoj hauv kev nrawm dua los nrhiav thaj chaw
Lub tswv yim
- Ib cheeb tsam ib txwm siv cov duab plaub lossis plaub fab, xws li square metres lossis square centimeters. Ib lub xwmfab, raws li lub npe qhia, yog: ib lub xwmfab uas dav ib meter thiab ib meter ntev. Yog tias prism muaj txheej sab nrauv ntawm 50 square metres, nws txhais tau tias peb xav tau 50 lub xwmfab los npog tag nrho saum npoo ntawm prism.
- Qee tus kws qhia siv qhov tob tsis yog qhov siab. Lub sijhawm no zoo, tsuav yog koj sau txhua sab kom meej.
- Yog tias koj tsis paub tias ntu twg yog qhov siab tshaj ntawm prism, koj tuaj yeem hu rau ib sab siab. Qhov ntev feem ntau yog sab ntev, tab sis nws tsis muaj teeb meem tiag. Tsuav koj siv tib lub npe hauv txhua lo lus nug, koj yuav tsum tsis muaj teeb meem.
