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[veneta]

osnovata na triugalna piramida e ravnobedreniat triugulnik ABC s bedra AC=BC=10 i <ACB=120.okolniqt rub CD e perpendikuliaren na osnovata ABC.okolnata stena ABD skluchva s osnovata <45.da se nameri V na piramidata.da se nameri litseto na sechenieto na piramidata s ravnina minavashta prez osnovniqt rub AB i sredata P na okolniqt rub.

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[veneta]

1)neka CH e viso4ina v ABC.CH=CD.ot tr.ACH:CH=CAxcos60=>10x1/2=5=>CD=5. 2)Sabc=10x10xkor3:4=>S=25xkor3.........3)V=BH/3.........V=25Xkor3X5/3=125kor3/3............4)za PH pit.t.=5xkor5/2..................5)<PHC=f...=>cosf=5x5xkor5/2=25xkor5/2ot S`=Sxcosf