Okuqukethwe
i-convex quadrilateral - Lesi sibalo sejometri esitholakala ngokuxhuma amaphuzu amane endizeni okungafanele ilale emgqeni owodwa oqondile. Kulokhu, izinhlangothi ezakhiwe ngale ndlela akufanele zihlangane.
Ifomula yendawo
Ngokuhambisana nama-diagonal kanye ne-engeli ephakathi kwawo
Indawo (S) ye-convex quadrilateral ilingana nomzuzwana owodwa (uhhafu) womkhiqizo wama-diagonal ayo kanye ne-sine ye-engeli ephakathi kwawo.
Ezinhlangothini ezine (ifomula kaBrahmagupta)
Ukuze usebenzise ifomula, udinga ukwazi ubude bazo zonke izinhlangothi zesibalo. Kufanele futhi kwenzeke ukuchaza indilinga ezungeze i-quadrilateral.
p - i-semi-perimeter, ibalwa kanje:
Eduze kwe-radius yendilinga eqoshiwe kanye nezinhlangothi
Uma umbuthano ungabhalwa ku-quadrilateral, indawo yawo ingabalwa kusetshenziswa ifomula:
S = p ⋅ r
r iyindawo engaba yindilinga.
Isibonelo senkinga
Thola indawo ye-convex quadrilateral uma i-diagonals yayo ingu-5 cm no-9 cm futhi i-engeli phakathi kwayo ingu-30 °.
Isinqumo:
Sishintsha amanani u1bu2b esiwaziwa siwafake kwifomula bese sithola: S u5d 9/30 * 11,25 cm * XNUMX cm * sin XNUMX ° uXNUMXd XNUMX cm2.