What is the constant of proportionality? Write your answer as a whole number or decimal. (k = __) There's a huge sale at the grocery store, so Austen stocks up on his favorite breakfast cereal, Frosted Crunchy Bunches. As he puts the cereal boxes on a shelf in his pantry, he wonders if he has enough shelf space. There is a proportional relationship between the number of cereal boxes Austen stores on his pantry shelf, x, and the amount of shelf space (in inches) the boxes take up, y.

x (boxes)
2
3
4
6
y (inches)
6
9
12
18