The ratios 84/105 and 128/160 are proportional
Solution:
Given, two ratios are
and

We have to give two different reasons to support the answer.
Reason 1:
Now, we know that, numerators and denominators should be proportional to be two fractions in proportion.

So numerators and denominators are in proportion, then given two fractions are proportion.
Reason 2:
Now, values of two fractions must be equal:

So, values of two fractions are equal, then they are in proportion.
Hence, the given two fractions are in proportion.