Neman yanki na rectangular parallelepiped: dabara da misali

A cikin wannan ɗaba'ar, za mu yi la'akari da yadda za a lissafta saman filin layi na rectangular da kuma nazarin misalin warware matsala don gyara abu.

Tsarin yanki

Ana lissafta yankin (S) na saman kuboid kamar haka:

S = 2 (ab + bc + ac)

Ana samun dabarar kamar haka:

1. Fuskokin madaidaicin rectangular masu kama da rectangles ne, kuma fuskoki masu gaba da juna suna daidai da juna:
   • tushe guda biyu: tare da tarnaƙi a и b;
   • fuska hudu: tare da gefe a/b da tsayi c.
2. Ƙara wuraren dukkan fuskoki, kowannensu daidai yake da samfurin bangarorin tsayi daban-daban, muna samun: S = ab + ab + bc + bc + ac + ac = 2 (ab + bc + ac).

Misalin matsala

Yi la'akari da filin yanki na cuboid idan an san cewa tsawonsa shine 6 cm, nisa shine 4 cm, tsayinsa shine 7 cm.

Yanke shawara:

Bari mu yi amfani da dabarar da ke sama, mu musanya sanannun dabi'u a cikinta:

S = 2 ⋅ (6 cm ⋅ 4 cm + 6 cm ⋅ 7 cm + 4 cm ⋅ 7 cm) = 188 cm².