Mr. Dominguez invests $3,000 in a savings plan. The savings account pays an annual interest rate of 4.2% on the amount he put in at the end of each year. Create (and label) a graph in the coordinate plane to show the relationship between time and the amount of interest earned for the first 5 years of the investment. Is the relationship proportional? Why or why not? If so, what is the constant of proportionality?