The equation 0.04x = y is a directly proportional relationship between x and y with 0.04 as the constant of proportionality.
Directly proportional: Two values or constants are directly proportional when a change in one leads to the same change in the other. This is a more-more relationship.
The equation 0.04x = y represents a directly proportional relationship between x and y. In direct proportion, as one quantity increases, the other quantity increases at a constant rate. This is typically represented as y = kx, where k is the constant of proportionality. In this case, 0.04 is the constant of proportionality, indicating that for every unit increase in x, y increases by 0.04 units. If we plot this relationship on a graph, we will obtain a straight line that passes through the origin (0; 0).