[tex]\it a)\ \ Vom\ nota\ \ \ell\ -\ latura\ bazei,\ \ \ h=3\ell\\ \\ \mathcal{A}_{\ell}=3h\ell=3\cdot3\ell\cdot\ell=9\cdot\ell^2=144|_{:9} \Rightarrow \ell^2=16=4^2 \Rightarrow \ell=4\ cm\\ \\ b)\ \ \mathcal{V}=\mathcal{A}_b\cdot h=\dfrac{\ell^2\sqrt3}{4}\cdot3\ell=\dfrac{3\sqrt3}{4}\cdot \ell^3=\dfrac{3\sqrt3}{4}\cdot\ 4^3= 3\sqrt3\cdot4^2=48\sqrt3\ cm^3[/tex]
