Kanjani ukubala endaweni unxantathu?

Ngesinye isikhathi empilweni kunezimo lapho kudingeka lokumba inkumbulo beyofuna eside ukhohliwe ulwazi esikoleni. Ngokwesibonelo, kubalulekile ukuchaza indawo noma isimo esingunxantathu kwafika ukulungisa esilandelayo ifulethi noma indlu yangasese, futhi kubalulekile ukubala malini impahla ukushiya ebusweni nge shape esingunxantathu. Kwake kwaba nesikhathi lapho ungase ukuxazulula le puzzle emva kwamaminithi ambalwa, futhi manje ngabomvu uzama ukukhumbula indlela ukunquma indawo unxantathu?

Akubalulekile ngenxa yalokhu okwenzeka! Phela, kuyinto ejwayelekile, lapho ubuchopho bomuntu enquma shift ulwazi eside ubuningi endaweni ethile egumbini elikude, which they kwesinye isikhathi ngeke ngakho kalula isusiwe. Ngakho ungenawo ukuhlupheka ucinge ukhohlwe ulwazi esikoleni ukuxazulula le nkinga, lesi sihloko iqukethe izindlela ezahlukahlukene ezenza kube lula ukuthola indawo edingekayo unxantathu.

Kuyaziwa ukuthi lolu hlobo unxantathu ibizwa ngokuthi ipholigoni, okuyinto kukhawulwe inombolo ubuncane kungenzeka ezinhlangothini. Ngomqondo onabile, iyiphi ipholigoni zingahlukaniswa zibe onxantathu, yokuxhuma vertices zayo izingxenye ukuthi ungaweqi kuye. Ngakho-ke, uma wazi ukuthi ifomula kuhlaziywa indawo unxantathu, ungakwazi ukubala indawo cishe noma yikuphi ukuma.

Phakathi kwazo zonke onxantathu kungenzeka ezenzeka ekuphileni, ngemva kwezinhlobo ezithile yilezi: equilateral, isosceles futhi kwesokudla yomumo.

Indlela elula endaweni unxantathu ibalwa uma omunye engeli salo esifanele, okungukuthi, esimweni unxantathu kwesokudla. Kulula phawula ukuthi uhhafu we isikwele. Ngakho-ke, indawo elilingana isigamu umkhiqizo amaphathi akha phakathi kwabo engela kwesokudla.

Uma siyazi engamamitha unxantathu, kwehlisa ezisuka kwenye vertices zayo kolunye uhlangothi, nobude kulolu hlangothi, okuthiwa base, endaweni ibalwa njengoba umkhiqizo nengxenye ukuphakama isizinda. Ulotshwe ngaYe lo ifomula:

S = 1/2 * b * h, lapho

S - endaweni oyifunayo unxantathu;

b, h - ngokulandelana, ukuphakama kanye phansi unxantathu.

Kulula Ngakho ukubala indawo unxantathu isosceles, kusukela ukuphakama ahlukanise esesayidini engxenyeni, futhi kalula singenakulinganiswa. Uma kunqunywa endaweni unxantathu kwesokudla in a ukuphakama elula ukuthatha ubude omunye izinhlangothi obumba engela kwesokudla.

Konke lokhu kuyinto Yebo okuhle, kodwa indlela ukunquma ukuthi omunye engeli ilungelo unxantathu noma cha? Uma usayizi sibalo yethu incane, ungasebenzisa engela isakhiwo, unxantathu ukudweba, amakhadi noma ezinye izinto nge shape elingunxande.

Kodwa kuthiwani uma siba icebo esingunxantathu komhlaba? Kulokhu, ukuqhubeka kanje: esilinganisiwe esivela phezulu engela kwesokudla Kusolakala ngakolunye uhlangothi lwale multiple ibanga 3 (cm 30, 90 cm begodu 3 m), futhi ngakolunye uhlangothi is alinganisiwe e ingxenye efanayo njengoba multiple ibanga 4 (40 cm, 160 cm, 4 m). Manje kudingeka ukukala ibanga phakathi Endpoints yalezi izingxenye ezimbili. Uma kuvulwe ukubaluleka 5 nesibaya (50 cm, 250 cm, 5 m), kungashiwo wagomela ukuthi engela umugqa.

Uma wazi ubude ngamunye ezinhlangothini ezintathu sibalo yethu, endaweni unxantathu kungaba azimisele besebenzisa ifomula Heron sika. Ukuze ube nohlobo ngaphezulu elula, ukusebenzisa inani elisha, okuthiwa semiperimeter. Kuyinto isamba sazo zonke ezinhlangothini unxantathu yethu uhlukaniswa uba nengxenye. Ngemva semiperimeter abalwa, ungakwazi uqhubekele ndawo ukuzimisela ngokuvumelana ifomula:

S = sqrt (p (pa) (PB) (pc)), lapho

sqrt - impande square;

p - Inani semiperimeter (p = (a + b + c) / 2);

a, b, c - emaphethelweni (izinhlangothi) unxantathu.

Kodwa kuthiwani uma unxantathu ine ijamo okungajwayelekile? Kunezindlela ezimbili kungenzeka. Eyokuqala wabo ukuzama ukwehlukana sibalo ku onxantathu ezimbili kwesokudla-angled, isamba ezindaweni lapho ukubala eceleni bese kwengezwe ndawonye. Lokunye futsi, uma engela eyaziwa phakathi kwalezi zinhlangothi zombili futhi ubukhulu lezi zinhlangothi, sebenzisa ifomula:

S = 0.5 * ab * sinC, lapho

a, b - ohlangothini unxantathu;

c - igebe eliphakathi lezi zinhlangothi.

Icala wokugcina umkhuba akuvamile, kodwa yize kunjalo, empilweni konke kungenzeka, ngakho ifomula ngeke engadingekile letinikwe lapha ngenhla. Inhlanhla izibalo yakho!