The rate of change of the surface elevation of Lake Powell is;
Rate of change every 7 years = Decreasing at 545.3 ft every 7 years
Rate of change per year = Decreasing at 77.9 ft per year
This means rate of change for 7 years = 3899 - 3353.7 = 545.3 ft
Rate of change every 7 years = 545.3 ft every 7 years
545.3/7 = 77.9 ft
Thus, rate of change per year = 77.9 ft per year
Read more at; https://brainly.com/question/20705459