[tex]\it I)\ Schimb\breve am\ \ mezii\ \ \^{i}ntre\ \ ei:\\ \\ \dfrac{3}{5}= \dfrac{9}{15}\ \Rightarrow \dfrac{3}{9} = \dfrac{5}{15}[/tex]
[tex]\it II)\ \ Schimb\breve am\ \ extremii\ \ \^{i}ntre\ \ ei:\ \ \ \ \dfrac{3}{5}= \dfrac{9}{15}\ \Rightarrow \dfrac{15}{5} = \dfrac{9}{3}[/tex]
[tex]\it\ III)\ \ Invers\breve am\ rapoartele:\ \ \dfrac{3}{5}= \dfrac{9}{15} \Rightarrow\ \dfrac{5}{3}= \dfrac{15}{9}[/tex]
