[tex]\displaystyle\bf\\\frac{x}{y} =c\\\\\\\frac{y}{z} =\frac{1}{c} \\\\\\\frac{x}{z} =?\\\\\\\frac{x}{y} \cdot \frac{y}{z} =c\cdot \frac{1}{c} \\\\\\\boxed{\frac{x}{z} =1}[/tex]