
two quantities that have a constant ratio; expressed as y=x and y=kx where k is a nonzero constant 


two quantities that have a constant product; expressed as y=1/x and xy=k where k is a nonzero constant 


the nonzero constant k in the equation that expresses the the relationship between two variables x and y 


arithmetic in which letters are used to represent variables 


quantities that may have different values 


represents a mathematical relationship among variables 

Multiple Proportionalities 

when one quantity is proportional to each of two or more other variables, it is proportional to the product of those variables
d=nt, d=knt, k=d/nt

