Final answer:
The constant of proportionality in this scenario is approximately 15.85 inches per box.
Step-by-step explanation:
In a proportional relationship, the constant of proportionality represents the rate at which one quantity changes in relation to another quantity. To find the constant of proportionality in this scenario, we can use the formula y = kx, where y represents the amount of shelf space and x represents the number of cereal boxes. We can choose any set of data points from the given information and plug them into the formula to solve for k. Let's use the first data point (26, 412):
412 = 26k. Solving for k, we get k = 412/26 = 15.85. Therefore, the constant of proportionality is approximately 15.85 inches per box.