Sebakeng trapezoid ka

lentsoe Trapezoid sebelisoa ho hlalosa e le geometry sekhutlonne, tšoauoa ka thepa e itseng. Ho phaella moo, ho na le meelelo e mengata. The mehaho sebelisoa ha ho buuoa ka mamati ditshwani, lifensetere le mehaho e hahiloeng ka bophara ka botlaaseng le tapering tlhōrōng (ka mokhoa oa ho ngola ea Baegepeta). Lipapaling - ke ho ikoetlisa thepa, ka feshene - moaparo, baki kapa mofuta tse ling tsa liaparo ke sehiloe ho khetheha le setaele.

Lentsoe "trapezoid" le tsoa ho la Segerike, fetoleloa ka puo ea Serussia e bolela "tafole" kapa "lijo tse tafole". The le geometry Euclidean joalo bitsoa khonvekse sekhutlonne le para e 'ngoe ea mahlakoreng hanyetsa tse tšoanang le mong ho e mong hakaalo. Hoa hlokahala ho hopola tse ling litlhaloso e le hore ho fumana sebaka seo ba trapezoid ka. E tšoanang le mahlakoreng tsa khutlontsi li bitsoa makalana, 'me ba bang ba babeli - lehlakoreng. Bophahamo ba trapezoid ke sebaka se pakeng tsa le bokatlase ba. mola bohareng e nkoa e le mola o tlohang midpoints ya lehlakoreng. All likhopolo tsena (botlaaseng, bophahamo, moleng bohareng le mahlakoreng) ke metsoako ea khutlontsi, e leng ke a sebetsa nyeoe ea khethehileng ea sekhutlonne ka.

polelo Ka hona tšoaneleha hore sebaka seo ba trapezoid e ka fumanoa ho tloha ka moralo wa, e reretsoeng ho sekhutlonne: S = ½ • (a + ƀ) • H. Moo S - ke sebakeng seo, 'me a ƀ - e ka tlaase le e ka holimo warping, H - ke phahameng theolela ho tloha sekhutlo haufi le e le setsi ka holimo, perpendicular ho e le setsi tlaase. Ke hore, S o lekana le sehlahisoa halofo ea chelete e phahameng ea makalana ka. Ka mohlala, haeba ho trapezium botlaaseng - 6 'me 2 limilimithara,' me bophahamo ba eona e - 15 limilimithara, sebakeng sona e tla lekana le: S = ½ • (6 + 2) • 15 = 60 mm².

Ho sebelisa thepa e tsebahalang ea tetragon e, ho ka etsahala hore a bale sebakeng trapezoid ka. Ka 'ngoe ea lipolelo tse bohlokoa ka ho fetisisa e re moleng bohareng (denoted ke lengolo le M, le e le setsi sa litlhaku le ƀ) lekanang le chelete halofo ea makalana, e leng o lula e tšoanang. I.e. μ = ½ (a + ƀ). Kahoo, a emeng tsebahalang manolotsoeng moralo S sekhutlonne mola bohareng, re ka ngola ka mokgwa wa ho bala ka mokhoa o fapaneng: S = μ • H. Bakeng sa ho le joalo moo bohareng mola - 25 cm,, bophahamo - 15 cm,, sebakeng trapezoid le o lekana le: S = 25 • 15 = 375 cm².

Ho ea ka thepa e tsebahalang ea khutlontsi le tse peli mahlakoreng e tšoanang le ho ba setsi, ho inscribe le selikalikoe le r e radius ho eona ka feela ka tjhelete e ya botlaaseng hlokahala tla lekanang Balang tsa mahlakore a eona lateral. Feta moo, haeba le trapezoid ke isosceles (khr, lekanang mahlakore a eona: mdlody = d), 'me e boetse e tsejoa angle botlaaseng alpha, ho ka fumanoa, se sebaka sa trapezoid moralo: S = 4r² / sinα,' me bakeng sa a sebetsa nyeoe ea ho khetheha ha α = 30 °, S = 8r². Ka mohlala, haeba ho hlaha ka lehlakoreng le ka e 'ngoe ea makalana ke 30 °, le selika-likoe ngotsoe ka radius ea 5 e dm, ebe sebakeng sena ba khutlontsi tla ho lekana le: S = 8 • 5² = 200 dm².

U ka boela ua fumana sebaka sa trapezoid e, ho roba eona likoto, a bale sebakeng ka mong le phaella ka ho re makgabane tsena. Ho ke ke molemo ho nahana ka dikgetho tse tharo khoneha:

1. mahlakoreng le dikhutlo botlaaseng baa lekana. Tabeng ena, ho trapezoid e bitsoa isosceles.
2. Haeba e mong lateral lehlakoreng liforomo dikhutloteng nepahetseng le botlaaseng, ke hore, perpendicular ho yona, ka nako eo sena tla bitsoa trapezoid likhutlo li 'nè.
3. Sekhutlonne oo mahlakoreng a mabeli a bapileng. Tabeng ena, pharallelokeramo ho ka nkoa e le taba e khethehileng.

Bakeng sa isosceles trapezoid sebakeng ke bala likarolo tse peli tse lekanang ya ya khutlonnetsepa dikhutlotharo S1 = S2 (bophahamo ba tsona ke bona ba bolelele ba trapezoid H, le dikhutlotharo botlaaseng halofo phapang trapezoid ½ makalana [e - ƀ]) le S3 khutlonne sebakeng (lehlakoreng le leng e le e ka holimo botlaaseng ƀ, 'me e mong - bophahamo ba H). Boo ho latela hore sebaka seo sa trapezoid S = S1 + S2 + S3 = ¼ (a - ƀ) • H + ¼ (a - ƀ) • H + (ƀ • H) = ½ (a - ƀ) • H + (ƀ • H). Bakeng sa trapezoid sebakeng likhutlo li 'nè ke chelete ea mapatlelong a triangolo le quadrangle: S = S1 + S3 = ½ (a - ƀ) • H + (ƀ • H).

Curvilinear trapezoid ka ho pharalla ha sehlooho sena, trapezoid sebakeng tabeng ena e balwa sebelisa integrals.