[tex]\text{Raportul ariilor a 2 triunghiuri asemenea, } \\ \text{este egal cu raportul patratelor perimetrelor} \\ \\ \frac{A_1}{A_2}= \frac{P_1^2}{P_2^2} \\ \\ \frac{4}{A_2}= \frac{10^2}{25^2} \\ \\ A_2= \frac{4*25^2}{10^2} =\frac{4*25*25}{100}=\frac{100*25}{100}= \boxed{25\;cm^2}[/tex]
