#### Check whether 3.5,4.9,3 and 4.2 are in proportion or not.

We have :

$3.5:4.9=\frac{3.5}{4.9}=\frac{35}{49}=\frac{5}{7}=5:7$

$3:4.2=\frac{3}{4.2}=\frac{30}{42}=\frac{5}{7}=5:7$

$\therefore \, 3.5:4.9 ::3:4.2$

Hence the numbers 3.5,4.9,3 and 4.2 are in proportion.