Answer:
Not a Proportional Relationship ; No Constant of Proportionality
Explanation:
Consider the first example, 4 hours of parking costs $ 10. From this we can derive the ratio 4 : 10, so that hours parked : fee for parking is a common ratio among the two examples, the other being 5 : 12;


Considering that the fractions when compared are not similar, ( 2 / 5, and 5 / 12 ) they don't have a proportional relationship, and thus have no constant of proportionality
Solution; Not a Proportional Relationship