a. The constant of proportionality is the value that relates the independent variable to the dependent variable in a proportional relationship.
b. Write an equation that represents this graph: It would be in the form y = kx, where k is the constant of proportionality and x is the independent variable.
c. This is a proportional relationship because the y-intercept is 0. In a proportional relationship, the y-intercept is always 0.