[tex]\displaystyle\\
\text{In triunghiul AMC cunoastem Baza AC si inaltimea MN.}\\\\
A_{\Delta AMC}=\frac{AC\times MN}{2}=\frac{28 \times25}{2}=\frac{700}{2}= \boxed{350~cm^2}\\\\
\text{Mediana imparte orice fel de triunghi in 2 triunghiuri echivalente.}\\
\text{Triunghiurile echivalente sunt triunghiuri care au aceeasi arie.}\\\\\Longrightarrow~~A_{\Delta AMB}=A_{\Delta AMC}=\boxed{350~cm^2}\\\\
\Longrightarrow~~A_{\Delta ABC}=A_{\Delta AMB}+A_{\Delta AMC}=350+ 350=\boxed{\boxed{700~cm^2}}
[/tex]