Since no function can be seen in this question, it may describe overall -the slope. The slope is the direction and magnitude of a relationship in the given graph. It introduces the relationship between two variables and is called correlation. Proportionality or variation is state of relationship or correlation between two variables It has two types: direct variation or proportion which states both variables are positively correlation. It is when both the variables increase or decrease together. On the contrary, indirect variation or proportion indicates negative relationship or correlation.