[tex]\it \Delta BCF- dreptunghic,\ m(\hat{C})=90^o\\ \\ BC=50\ cm\ (cu\ T.P.)\\ \\ d(C.\ BF)=\dfrac{BC\cdot CF}{BF}=\dfrac{40\cdot30}{50}=24\ cm\\ \\ \underline{Obs.}\\ \\ \Delta BCF- pitagoreic[/tex]
