Ungayithola kanjani indawo yengxantathu eyinxantathu ngendlela engavamile

Esifundweni se-geometry esikoleni esiphakeme, sonke satshelwa ukuthi singayithola kanjani indawo enxantathu efanele . Nokho, ngaphakathi kohlelo lwezifundo zesikole, sithola ulwazi oludingekayo kuphela futhi sifunde izindlela ezijwayelekile kakhulu zokubala. Zikhona izindlela ezingavamile zokuthola le nzuzo?

Njengesingeniso, ake sikhumbule ukuthi yimuphi unxantathu obhekwa njengechungechunge, futhi uchaza nomqondo wendawo.

Unxantathu onxantathu ungumfanekiso we-geometric ovaliwe, owodwa wama-angles angu-90 ⁰ . Imiqondo engokwemvelo encazelo yelunxantathu elungile imilenze kanye ne-hypotenuse. Ngemilenze lisho izinhlangothi ezimbili, okuyinto ekhoneni lehlangothini yakha ikona elifanele. I-hypotenuse iphikisana ne-angle engakwesokudla. Unxantathu olungileyo ungaba isosceles (izinhlangothi zawo ezimbili zizoba nenani elifanayo), kodwa ngeke lilingane (zonke izinhlangothi ezilinganayo nobude obufanayo). Izincazelo zokuphakama, ama-median, ama-vectors kanye neminye yemathematika ngeke zixoxwe ngokuningiliziwe. Kulula ukuthola ezincwadini zokubhekisela.

Isikwele sesonxantathu esifanele. Ngokungafani nama-rectangles, ukubusa kwe Umsebenzi wezinhlangothi ekunqumeni indawo enxantathu awusebenzi. Uma sikhuluma ulimi olomile wemigomo, khona-ke endaweni yongxantathu sisho indawo yalesi sibalo ukuba sithathe ingxenye yendiza evezwe ngenombolo. Kunzima ukubona, uzovuma. Ngeke sizame ukungena ngokujulile ngencazelo, umgomo wethu akulona lokhu. Masihambe enhloko - ukuthi ungayithola kanjani indawo yesonxantathu esifanele? Ngeke senze izibalo ngokwethu, sizokhombisa kuphela amafomula. Ngalokhu sichaza isaziso: A, B, C - izinhlangothi zontathu, imilenze - AB, BC. I-angle ye-ACB iqondile. S yindawo yendxantathu, h _{n n} ukuphakama kontathu, lapho nn kuhlangothini oluye lwashiywa khona.

Indlela 1. Indlela yokuthola indawo yexantathu elungile, uma ubukhulu bemilenze yayo yaziwa

S = 0.5 * a * b

Indlela 2. Thola indawo yexantathu elungile le-isosceles

S = 0.5 * h _BC * BC

Indlela 3: Bala indawo ngecande

Sigcwalisa unxantathu ohlangothini oluxubile kuya esigcawini (uma unxantathu Isosceles) noma umugqa. Sithola i-quadrilateral elula eyakhiwe ama-triangles angama-2 angama-rectangular. Kulokhu, ukubaluleka kwendawo yomunye wabo kuzolingana nengxenye yendawo yesitho esitholakalayo. I-ngqangi ibalwa ngumkhiqizo wezinhlangothi. Ake sikhethe leli xabiso M. Inani elidingekayo le ndawo lizolingana nengxenye kaM.

S = 0.5 * M

Indlela 4. "Izintambo zePythagorean". Idokhumenti edumile yasePythagoras

Sonke sikhumbula amazwi akhe: "isibalo sezikwele zemilenze ...". Kodwa akuwona wonke umuntu ongakwazi Yisho, futhi lapha "ezinye izibhulu". Iqiniso liwukuthi kusukela ekuqaleni uPythagoras wafunda ukuhlanganiswa kwezindawo zezikwele ezakhiwe ezinhlangothini zonxantathu eqondile. Ngemva kokuthola ukujwayela kwesilinganiso sezinhlangothi zezikwele, wakwazi ukuthola ifomula elaziwa sonke. Ingasetshenziswa ezimweni lapho inani lalawo maqembu lingabonakali.

Indlela 5. Ungayithola kanjani indawo enxantathu ene-angled nge-formula kaHeron

Kuyindlela elula yokubala. Ifomula ibonisa ukubonakaliswa kwendawo yenxantathu ngokusebenzisa izindinganiso zamanani ezinhlangothini zayo. Ukuze kubalwe kubalulekile ukwazi amanani azo zonke izinhlangothi zontathu.

S = (p-AC) * (p-BC), lapho p = (AB + BC + AC) * 0.5

Ngaphezu kwalokhu okungenhla, kunezinye izindlela eziningi zokuthola ukubaluleka kwalowo muntu ongaqondakali njengonxantathu. Phakathi kwabo: ukubalwa ngendlela yokubhalisa noma umbuthano ojikelezayo, ukubala ngokusebenzisa izixhumanisi zama-vertic, ukusetshenziswa kwama-vectors, inani eliphelele, amasono, amathangathi.