[tex]\bf ABCD-romb,\ AC\cap BD=\{O\},\ \mathcal{A}_{ABCD}=48\ cm^2,\ \ h=6\ cm.\\ \\ \ell=?\ \ \mathcal{A}_{AOB}=?\\ \\ \\ \it Rezolvare:\\ \\ \mathcal{A}_{AOB}=\dfrac{\mathcal{A}_{ABCD}}{4}=\dfrac{48}{4}=12\ cm^2\\ \\ \\ \mathcal{A}_{ABCD}=\ell \cdot h \Rightarrow 48=\ell \cdot6\Big|_{:6} \Rightarrow \ell = 8\ cm[/tex]
