Ukuthola indawo kanxantathu: ifomula nezibonelo

triangle – Lesi sibalo sejiyomethri esinezinhlangothi ezintathu ezakhiwe ngokuxhuma amaphuzu amathathu endizeni engeyona eyomugqa ofanayo oqondile.

Amafomula ajwayelekile okubala indawo kanxantathu

Isisekelo nobude

Indawo (S) kanxantathu ilingana nengxenye yomkhiqizo wesisekelo sawo kanye nokuphakama kwawo.

Ifomula ye-Heron

Ukuze uthole indawo (S) kanxantathu, udinga ukwazi ubude bazo zonke izinhlangothi zawo. Kubhekwa njengokulandelayo:

p - i-semi-perimeter kanxantathu:

Ngezinhlangothi ezimbili kanye ne-engeli ephakathi kwazo

Indawo kanxantathu (S) ilingana nengxenye yomkhiqizo wezinhlangothi zayo ezimbili kanye ne-sine ye-engeli ephakathi kwazo.

Indawo kanxantathu ongakwesokudla

Indawo (S) yesibalo silingana nengxenye yomkhiqizo wemilenze yawo.

Indawo kanxantathu we-isosceles

Indawo (S) ibalwa kusetshenziswa ifomula elandelayo:

Indawo kanxantathu olinganayo

Ukuthola indawo kanxantathu ojwayelekile (zonke izinhlangothi zesibalo ziyalingana), kufanele usebenzise eyodwa yamafomula angezansi:

Ngobude bohlangothi

Ngobude

Izibonelo zemisebenzi

Umsebenzi 1

Thola indawo kanxantathu uma olunye lwezinhlangothi zalo luyi-7 cm nobude obudonseleka kuwo bungama-5 cm.

Isinqumo:

Sisebenzisa ifomula lapho ubude becala nobude bubandakanyeka khona:

S = 1/2 ⋅ 7 cm ⋅ 5 cm = 17,5 cm².

Umsebenzi 2

Thola indawo kanxantathu enezinhlangothi ezi-3, 4 no-5 cm.

1 Isixazululo:

Masisebenzise ifomula yeHeron:

I-semiperimeter (p) = (3 + 4 + 5) / 2 = 6 cm.

Ngenxa yalokho, i- S = √6(6-3)(6-4)(6-5) = I-6 cm².

2 Isixazululo:

Ngenxa yokuthi unxantathu onamacala 3, 4 no-5 ungunxande, indawo yawo ingabalwa kusetshenziswa ifomula ehambisanayo:

S = 1/2 ⋅ 3 cm ⋅ 4 cm = 6 cm².