If the y and x axis rise/fall in the same way, it is proportional. For example, if for every one hour you work you get three dollars, the graph would look something like a simple line. If the problem is: Every time a leaf fell, the cat would walk around twice, it is proportional, albeit random. If the leaf fell 5 times, the cat would walk 10. If the cat walks around 3 times, then 0, then 18 every leaf fall, it would not be proportionate.