You first start with the ratio:
12:28
Now you see what goes in it, seems like 2, because it's an even number.
12 / 2 = 6
24 / 2 = 12
6:12 can still be divided.
6 / 2 = 3
12 / 2 = 6
3:6 is the final product, now we have to turn it into a fraction.
3 is half of 6 so we could turn it into a one and a half fraction.
1/2
Our final product will be 1/2.
Hope this helps!~