[tex]\text{Cu teorema cosinusului il putem afla pe AC.}\\
AC^2=AB^2+BC^2-2\cdot AB\cdot BC\cdot \cos B\\
AC^2=4+16-2\cdot \not2\cdot 4\cdot \dfrac{1}{\not2}\\
AC^2=20-8=12\Rightarrow AC=\sqrt{12}=2\sqrt{3}\\
P_{\Delta ABC}=AB+AC+BC=2(3+\sqrt3) cm[/tex]
