[tex]\displaystyle\\
10)\\\\
\frac{AM}{AB} = \frac{1}{4} \\\\
\frac{AN}{NC} = \frac{1}{3} ~~\text{\bf Calculam proportia derivata:}\\\\ \frac{AN}{AN+NC} = \frac{1}{1+3} ~\Longrightarrow ~\frac{AN}{AC} = \frac{1}{4} \\\\
\text{Conform reciprocei Teoremei lui Thales avem:}\\\\
\bf Daca:
\frac{AM}{AB} = \frac{AN}{AC} =\frac{1}{4}, \text{\bf atunci } MN||BC [/tex]
