if we have the following ratio 17/30 and multiply both terms by 2, we obtain 34/60
[tex]\frac{17}{30}=\frac{17\cdot2}{30\cdot2}=\frac{34}{60}[/tex]
on the other hand, if we have the ratio 3.4/6 and then we multiply the terms by 10, we also obtain 34/60
[tex]\frac{3.4}{6}=\frac{3.4\cdot10}{6\cdot10}=\frac{34}{60}[/tex]
in that way, we can see that both ratios, 17/30 and 3.4/6 are proportional
[tex]\frac{17}{30}=\frac{3.4}{6}[/tex]
