Final answer:
None of the provided options (a through i) have the same constant of proportionality as the equation y=5x because they represent scenarios where x is constant, and thus the proportionality constant would be 0.
Step-by-step explanation:
The problem asks us to identify which relationships have the same constant of proportionality between y and x as the equation y=5x. Since there is no x term in options (a) through (i), they represent situations where x does not vary; that is, x is constant. So the constant of proportionality (k) in the equation y=kx is actually 0 in each case, because multiplying 0 by any value of x will always yield a y value of 0, which does not match the given equation y=5x. Therefore, none of the provided options have the same constant of proportionality as the equation y=5x.