Explanation:
6/9 divide top and bottom by 3 to get 2/3
Now reduce each of the fractions to the lowest terms, and look for one that gives 2/3.
12/8 = 3/2 (divide by 4 top and bottom)
8/12 = 2/3 (divide by 4 top and bottom) This is a solution
10/12 = 5/6 (divide by 2 top and bottom)
8/13 (cannot be reduced)
Therefore the second fraction (8/12) forms a proportion with 6/9.