For all who are learning this subject Caution
In a proportional relationship, the graph will be a straight line that goes through the origin. While each point on the line represents a proportional relationship, each point may not be a reasonable solution.

For example, if a graph shows that for every 1 text sent there are 3 texts received, does it then make sense that if 0.5 texts are sent that 1.5 texts are received? Of course not because we cannot send 0.5 texts or have a group of 1.5 people receiving those texts!