In the year 1997, the surface elevation of Lake Powell was 3887 feet above sea level. In the year 2001, the surface elevation of Lake Powell was 3577.4 feet above sea level.
The surface elevation of Lake Powell is
at a rate of
well, 3577.4 is less than 3887, so ...
how many feet in how many years?
To find the rate at which the surface elevation of Lake Powell is changing, we can use the formula:
Rate of change = (Change in elevation) / (Change in time)
Given that the surface elevation in 1997 was 3887 feet above sea level, and in 2001 it was 3577.4 feet above sea level, we can calculate the change in elevation:
Change in elevation = 3577.4 - 3887 = -309.6 feet
The sign is negative because the elevation decreased.
Now, we need to find the change in time. From 1997 to 2001, there are 4 years:
Change in time = 2001 - 1997 = 4 years
So the rate of change in the surface elevation of Lake Powell is:
Rate of change = -309.6 / 4 = -77.4 feet per year
Therefore, the surface elevation of Lake Powell is decreasing at a rate of 77.4 feet per year.