A proportional relationship is when you cross multiply, and the numbers are equal. See the first few numbers.
1 x 12 = 12
3 x 4 = 12
Now solve.
3 x 16 = 48
48/12 = 4
20 x 8 = 160
160/5= 32
The first answer is 4, and the second is 32.
Hope this helps! :)