Obtuse daim duab peb sab: qhov ntev ntawm lub sab, lub sum ntawm cov ces kaum. Piav obtuse daim duab peb sab

Txawm preschool cov me nyuam paub dab tsi nws zoo li ib tug daim duab peb sab. Tab sis yog li ntawd, yog dab tsi lawv hais mav twb pib to taub lub tsev kawm ntawv. Ib hom yog ib qho obtuse daim duab peb sab. To taub nws yog dab tsi yooj yim saib yog hais tias ib daim duab nrog nws daim duab. Nyob rau hauv kev tshawb xav, qhov no thiaj hu ua "tej yam yooj yim polygon" nrog peb sab thiab vertices, yog ib tus uas yog ib tug obtuse kaum sab xis.

Peb to taub nrog cov ntsiab lus

Lub geometry paub qhov txawv cov hom ntawm cov duab uas muaj peb sab: lub mob-angled, right-angled thiab obtuse-angled cov vajvoos peb sab. Cov khoom ntawm cov yooj yim uas yog tib yam rau txhua leej txhua tus. Yog li ntawd, rau tag nrho cov hom yuav muaj cai no tsis sib xws. Lub sum ntawm cov lengths ntawm ob sab yog kom yuav tsum tau ntau tshaj li ib feem peb-tog extension.

Tab sis nyob rau hauv thiaj li yuav tau nco ntsoov tias peb tham txog ib tug ua tiav daim duab, ntau dua li ib txheej ntawm ib tug neeg peaks, koj yuav tsum tau xyuas kom ua raws li qhov yooj yim yuav tsum tau hais tias tus sum obtuse kaum ntawm ib tug peb tog yog sib npaug zos rau ^180. Yog ib yam muaj tseeb rau lwm yam nuj nqis uas muaj peb sab. Txawm li cas los, nyob rau hauv ib tug obtuse daim duab peb sab, ib tug ces kaum yuav txawm ntau ^90, thiab tshuav ob yog ua txhua yam rau yuav ntse. Nyob rau hauv cov ntaub ntawv no, nws yuav tsum yog tus ntau tshaj plaws lub opposite lub coos sab. Txawm li cas los, qhov no yog tsis tag nrho cov khoom ntawm ib tug obtuse-angled daim duab peb sab. Tab sis cia li paub txog cov nta, cov tub ntxhais kawm muaj peev xwm daws tau ntau yam teeb meem hauv geometry.

Rau txhua polygon nrog peb vertices kuj muaj tseeb hais tias, thaum ntxiv rau ib tog, peb tau txais lub kaum sab xis, qhov luaj li cas ntawm cov uas yuav tsum tau sib npaug zos rau cov sum ntawm ob tug non-nyob ib sab sab hauv vertices nrog nws. Puag ncig obtuse daim duab peb sab yog xam nyob rau hauv tib txoj kev raws li rau lwm yam nuj nqis. Nws yog tus sum ntawm cov lengths ntawm tag nrho nws cov sab. Yuav kom txiav txim seb lub cheeb tsam ntawm daim duab peb sab thom nug txawv qauv tau muab, nyob ntawm seb yam ntaub ntawv uas yog Ameslikas tam sim no.

muaj tseeb cim

Ib qho tseem ceeb nyob rau hauv kev daws cov teeb meem ntawm geometry yog qhov tseeb daim duab. Feem ntau lej xib fwb hais tias nws yuav pab tau tsuas yuav pom tau dab tsi yog muab thiab dab tsi yog yuav tsum tau ntawm koj, tab sis 80% los ze zog mus rau lub cov lus teb. Nws yog yog li ntawd ib qho tseem ceeb kom paub tias yuav ua li cas los tsim kom tau ib tug obtuse daim duab peb sab. Yog hais tias koj xav tau ib tug cia li hypothetical daim duab, koj yuav tau kos tej duab ua nrog peb sab li hais tias ib tug ces kaum yog lawm ^90.

Yog hais tias ib tug tej yam muab qhov tseem ceeb ntawm sab lengths los yog cov ces kaum degrees, daim duab yuav tsum tau obtuse daim duab peb sab nyob rau hauv raws li lawv. Nws yog tsim nyog los sim mus depict meej lub siab tshaj plaws ces kaum, xam lawv siv ib tug protractor, thiab proportionally qhov chaw cov ntaub ntawv nyob rau hauv cov nqe lus ntawm cov zaub sab.

ntsiab kab

Feem ntau, me ntsis schoolchildren paub yog vim li cas koj nyiam cov neeg los yog lwm yam nuj nqis. Tej zaum lawv yuav tsis tau tsuas yog txwv tsis pub ntaub ntawv txog yuav ua li cas obtuse daim duab peb sab thiab tus duab plaub. Kev kawm txog zauv kawg muab hais tias lawv cov kev paub ntawm cov ntxwv yooj yim ntawm cov nuj nqis yuav tsum tau ntau yam dua.

Yog li, txhua tus menyuam kawm ntawv yuav tsum muaj tseeb ntsiab txhais ntawm bisector, nruab nrab, thiab cov perpendicular qhov siab. Nyob rau hauv tas li ntawd, nws yuav tsum paub lawv cov kev zog.

Yog li, lub kaum sab xis bisector yog muab faib nyob rau hauv ib nrab, thiab kev coj rov qab - mus rau hauv cov kab txiav uas yog xwm yeem mus rau ib sab sab.

Cov theem nrab faib txhua daim duab peb sab mus rau hauv ob sib npaug zos chaw. Thaum lub point qhov twg lawv tshuam, txhua tus uas yog partitioned ua ob lengths nyob rau hauv tus piv 2: 1, thaum saib los ntawm lub sab saum toj, los ntawm uas nws tuaj. Ib tug loj theem nrab ib txwm muaj los nws qis sab.

Tsis muaj tsawg mloog yog them mus rau lub chaw siab tshaj. Nws yog perpendicular mus rau lub opposite sab ntawm lub kaum sab xis. Lub qhov siab ntawm cov obtuse daim duab peb sab nws muaj nws tus yam ntxwv. Yog hais tias nws yog nqa tawm los ntawm tus ntse ntsis, nws tsis poob rau sab ntawm ib tug yooj yim polygon, thiab nyob rau hauv nws cov continuation.

Lub perpendicular - ib ya uas mus los ntawm qhov chaw ntawm lub ntug ntawm daim duab peb sab. Nyob rau tib lub sij hawm nws yog nyob rau ntawm txoj cai lub.

Ua hauj lwm nrog lub voj voog

Thaum pib ntawm txoj kev tshawb ntawm cov geometry ntawm cov me nyuam txaus kom to taub yuav ua li cas rau kos ib obtuse daim duab peb sab, kawm kom paub qhov txawv los ntawm lwm hom, thiab nco ntsoov nws yooj yim zog. Tab sis high school cov tub ntxhais kawm uas paub tsis txaus. Piv txwv li, nyob rau hauv cov tub ntxhais Lus nug cov lus nug txog lub circumscribed thiab inscribed lub voj voog. Tus thawj koom peb vertices ntawm ib tug daim duab peb sab, thiab lwm yam muaj ib qho taw tes rau tag nrho cov tog.

Tsim lub inscribed los yog circumscribed obtuse daim duab peb sab yog nyuab npaum li cas, vim hais tias qhov no koj yuav tsum pib los xyuas seb qhov twg koj xav kom lub chaw ntawm lub voj voog thiab nws voos kheej-kheej. Los ntawm txoj kev, yuav ua tau ib tug tseem ceeb lub cuab tam nyob rau hauv cov ntaub ntawv no tsis yog tsuas yog ib tug cwj mem nrog ib tug kav, tab sis kuj yog ib tug compass.

Cov tib teeb meem tshwm sim nyob rau hauv constructing lub inscribed uas nrog peb sab. Thom nug tau muab ntau yam qauv uas tso cai rau peb los txiav txim seb lawv qhov chaw nyob raws li meej li sai tau.

inscribed cov vajvoos peb sab

Raws li hais ua ntej lawm, yog ib lub voj voog kis tau los ntawm tag nrho cov peb vertices, ces nws yog hu ua tus circumscribed lub voj voog. Nws lub ntsiab feature yog hais tias nws yog nws. Yog xav paub yuav ua li cas yuav tsum tau positioned circumscribed lub voj voog obtuse daim duab peb sab, ib tug yuav tsum nco ntsoov hais tias nws chaw yog nyob rau ntawm cov kev tshuam ntawm peb midperpendiculars uas mus rau lub sab ntawm cov duab. Yog hais tias ib tug mob-angled polygon nrog peb vertices, qhov no taw tes yuav hauv nws, nyob rau hauv ib tug obtuse - tshaj.

Paub, piv txwv li, hais tias ib tug ntawm lub sab ntawm ib tug obtuse-angled daim duab peb sab yog sib npaug zos rau nws voos kheej-kheej, nws yog tau mus nrhiav lub kaum sab xis uas yog lus dag opposite tus naas ej ntsej muag. Nws sine yog sib npaug zos rau cov kev tshwm sim ntawm faib qhov ntev ntawm lub zoo-paub sab rau 2R (nyob qhov twg R - yog lub voos kheej-kheej ntawm lub voj voog). Qhov ntawd yog kev txhaum lub yog sib npaug zos rau ½. Li no, lub kaum sab xis yog sib npaug zos rau ^150.

Yog hais tias koj yuav tau mus nrhiav lub voos kheej-kheej ntawm lub vajvoog obtuse daim duab peb sab, ces koj pab qhia txog qhov ntev ntawm nws sab (c, v, b) thiab nws cheeb tsam S. Vim hais tias cov voos kheej-kheej yog xam raws li nram no: (c x v x b): 4 x S. Los ntawm txoj kev, nws tsis muaj nqi nws yog dab tsi koj zoo ntawm daim duab: ib tug ntau yam obtuse daim duab peb sab, ib tug ceskaum, mob-angled ncaj-los yog. Nyob rau hauv tej teeb meem no, ua tsaug rau cov mis, koj yuav kawm tau ib tug muab cheeb tsam ntawm ib tug polygon nrog peb sab.

daim duab peb sab

Nws tseem yog heev mus ua hauj lwm nrog lub inscribed lub voj voog. Raws li ib tug ntawm cov qauv, lub ib voos ncig ntawm xws li ib tug duab, ½ khoo los ntawm cov puag ncig yuav ua ncaj rau cov cheeb tsam ntawm daim duab peb sab. Txawm li cas los, rau nws cov nrhiav koj yuav tsum paub rau ib feem ntawm ib tug obtuse-angled daim duab peb sab. Tom qab tag nrho cov, nyob rau hauv kev txiav txim los mus txiav txim ½ perimeter, nws yog tsim nyog los muab lawv cov ntev thiab muab faib ua 2.

Yuav kom to taub qhov twg koj xav kom lub chaw ntawm lub vajvoog inscribed nyob rau hauv obtuse daim duab peb sab, nws yog tsim nyog los siv peb lub bisector. Qhov no kab, uas faib cov fab nyob rau hauv ib nrab. Nws yog ntawm cov kev tshuam thiab yuav qhov chaw ntawm lub voj voog. Nyob rau hauv cov ntaub ntawv no, nws yuav tsum equidistant los ntawm txhua lub tog.

Lub voos kheej-kheej ntawm ib lub voj voog inscribed nyob rau hauv lub obtuse-angled daim duab peb sab sib npaug rau hauv lub square hauv paus ntawm lub private (pc) x (pv) x (PB): p. Nyob rau hauv cov ntaub ntawv no, p - yog ib tug ib nrab-perimeter ntawm lub daim duab peb sab, c, v, b - sab ntawm nws.