Answer :

First, set them equal to each other:

[tex]\frac{0.2}{1.8} =\frac{1}{0.9}[/tex]

Now if this is true, then .2 x .9 should equal 1.8 x 1.

.2 x . 9 = .18       1.8 x 1 = 1.8

So they are not a proportion.