tamam onda hemfikiriz
$\dfrac {a} {b}=\dfrac {2} {3}$ = $\dfrac {a} {b}=\dfrac {2.2} {2.3}$
$ \dfrac {b} {c}=\dfrac {2} {5}$ = $ \dfrac {b} {c}=\dfrac {3.2} {3.5}$
$\dfrac {a} {b}=\dfrac {4} {6}$ $a=4$
$ \dfrac {b} {c}=\dfrac {6} {15}$ $c=15$
$ \dfrac {a} {c}=\dfrac {4} {15}$