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. Elaborately,
the opposite of what happens to direct variation. One increases with the other
variables, you got it, decreases. This correlations are important to consider
because you can determine and identify how two variables relates with one
another.
Notice x = y (direct), y=1/x (indirect)
