The graph shows a proportional relationship because it is a line, and the difference between each point is the same. the graph shows a proportional relationship because it is a line, and each x-value is a multiple of 2. the graph does not show a proportional relationship because each point written as a ratio gives a different value. the graph does not show a proportional relationship because a line that increases by 1 in the y-value cannot have a constant of proportionality.