Indlela yokuthola kwendawo trapezoid?

Ngaphambi kanjani ukuthola kwendawo trapezoid, kubalulekile ukuba sinikeze incazelo yalo.

A-Line - umumo weJiyomethri nge emagumbini amane lapho izinhlangothi ezimbili kukhona parallel nomunye, kanti lawa amanye amabili - akukho. izinhlangothi ezimbili parallel nomunye, ezibizwa ngokuthi yizisekelo, futhi okungezona parallel - ohlangothini. Uma amaqembu, okuyizinto lateral, alinganayo, i trapezoid isosceles kuyothiwa. Uma empambana akha engela kwesokudla, kuba elingunxande.

Esikhathini algebra umbono ngaphezulu trapezium curvilinear - sibalo ngaphansi waqonda iphahlwe ngakolunye uhlangothi lwale eksisi x, kanye nezinye - igrafu umsebenzi y = f (x) b futhi kuchazwe kwi isikhawu [a; b]

Indlela yokuthola kwendawo trapezoid

Kubalwa enjalo sibalo Jomethri ngu S ifomula = 0,5 * (a + b) * h, lapho kanye nobude elisekela trapezoid, futhi h - ukuphakama kwalo.

Isibonelo. Dana trapezoid, omunye base okuyinto 2 cm, owesibili - 3 cm, futhi ukuphakama - 4 cm endaweni alindele ifomula, sithola umphumela :. S = 0, 5 * (2 + 3) * 4 = 12 cm2.

Kusukela indlela efanayo lokhu, njengokuba nazi indawo sibalo, ukuphakama, ubude omunye amaqembu, kungatholakala ubude nezinye. Eyesibili inketho - kokwazi ubude izinhlangothi futhi endaweni trapezoid, kungenzeka ukuthola ukuphakama kwalo.

Isibonelo. Dana trapezoid, lapho besisekelo esisodwa isikhathi eside kunaleso abanye izikhathi 3. Ukuphakama sibalo - 3 cm, endaweni - 24sm2. Ufuna ukuthola ubude kokubili elisekela.

Isinqumo. Usayizi ibalwa ifomula S elandelayo = 0,5 * (a + b) * h. Kusukela nemibandela inkinga kucace ukuthi uhlangothi kunangendlela omunye 3 izikhathi, ngakho-ke, i-= 3b. Miselela i-formula futhi ukuthola S = 0,5 * (a + 3b) * h = 0,5 * 4B * h. Ngenxa yalokho, sithola S = 2c * h, okungukuthi, = S / 2 amahora. Obambele amanani ezinombolo futhi ukuthola = 6 cm, a = 18 cm.

Nokho, lena akuyona indlela kuphela ukuthi ungakwazi ukunquma indawo yalesi sibalo. Ngo indlela yesibili, ngaphambi kokuba uthole indawo trapezoid, kungashiwo ihlukaniswe elula ngamajamo weJiyomethri: isikwele kanye onxantathu ezimbili (noma unxantathu, esimweni a trapezoid unxande). Kulokhu, endaweni Imininingwane izobalwa njengoba isamba izindawo kwalezi zibalo. Njengoba okuhlukile - ke kungenziwa alotshiwe isikwele eceleni kabani lateral ilingana ubude base emikhulu. Kulokhu, endaweni trapezoid kunqunywa njengoba umehluko endaweni isikwele kanye unxantathu.

Indlela yokuthola kwendawo unxande trapezoid? Sekuvele wawuthi a trapezoid unxande kungenziwa ngokuthi i trapezoid kabani isizinda (ukuyibiza a) kanye ohlangothini lateral aphambana, azakhele prima engela. Ngakho wathi sibalo avsd ngohlangothi lizophakama. Khona-ke, uma wazi ukuthi ubude zonke izinhlangothi 3, kungenzeka ukuthola indawo S sibalo = 0,5 * (a + b) * c.

Ifomula elula simiswe ngalendlela lelandzelako: S = a h *, lapho k - ubude umugca lohlukanisa emkhatsini we trapezoid, h - ukuphakama kwalo. Inkinga iwukuthi practice kulula ulinganise ubude base kuka ukuthola umugca losemkhatsini esifubeni. Futhi simi ngale ndlela:

Sikhishwe: scalene, engesiyena unxantathu trapezoid AVSD lapho izinhlangothi AB futhi CD kukhona izisekelo. Ngaphambi uthola indawo trapezoid kufanele izingxenye AC futhi vd yizinqamu 2 alinganayo, wokugubha iphuzu empambana izinhlamvu G no-C Khona-CC umugqa, aphethwe parallel phansi, futhi kuyoba umngcele maphakathi m trapezoid.

Elinye icala ekhethekile - lapho trapezoid equilateral. Ukuze ilingane zonke lezi amafomula (yebo, ngaphandle amafomula unxande). endaweni kwalo kungabhekwa kunqunywa kokwazi igebe eliphakathi izisekelo. Ifomula simiswe ngalendlela lelandzelako: S = (a + b) * c * isono (x) * 0.5, lapho futhi b - ubude besisekelo ohlangothini obuphelele c, futhi x - igebe eliphakathi kwabo.

Ngezinye izikhathi udinga ukucacisa indawo sibalo, hhayi kuphela e-geometry, kodwa futhi ku-algebra izixhumanisi. Kule ndaba, abafundi ukungabaza indlela ukuthola kwendawo trapezoid e izixhumanisi. Isimiso yokusebenzisa ikhompyutha kuyafana - sokunquma ubude izinhlangothi, njengoba umehluko uhlela isizinda amaphuzu ibalwa, futhi ukuphakama ifomula lokuqala ibalwa endaweni. Ukuphakama ezocatshangelwa umugqa oqondile sisuselwa ekhoneni omunye lezisekelo ukuba omunye base.

Ukuze sithole kwendawo trapezoid curvilinear eziyingxenye esemqoka.