The Constant of proportionality is equal to: 1/5
How to find the constant of proportionality?
The constant of proportionality is a fixed number that represents the ratio between two directly proportional quantities. In other words, if two variables, x and y, are directly proportional, their relationship can be expressed as y = kx, where k is the constant of proportionality.
Thus, the constant of proportionality for the given linear graph is also the slope and gotten from the formula:
k =

Using the coordinates (0, 0) and (5, 1), we have:
k = (1 - 0)/(5 - 0)
k = 1/5