[tex]\it b)\ \ BD=8\sqrt2cm(diagonala\ lui\ ABCD) \Rightarrow OB=\dfrac{8\sqrt2}{2}=4\sqrt2\ cm\\ \\ \Delta VOB-dreptunghic,\ \widehat{O}=90^o,\ \stackrel{T.P.}{\Longrightarrow}\ VO^2=VB^2=OB^2=\\ \\ =(8\sqrt2)^2-(4\sqrt2)^2=64\cdot2-16\cdot2=128-32=96=16\cdot6=4^2\cdot6\Rightarrow\\ \\ \Rightarrow VO=4\sqrt6\ cm[/tex]
[tex]\it c)\ MO-linie \ mijlocie\ \^{i}n\ \Delta VBD \Rightarrow MO||VD, \ iar\ VD\subset(VDC)\Rightarrow MO||(VDC)[/tex]
