linear equation rate of change

Question

In the year 1999, the surface elevation of Lake Powell was 3860 feet above sea level. In the year 2007, the surface elevation of Lake Powell was 3238.4 feet above sea level.

 

 Interpret the rate of change.

 

The surface elevation of Lake Powell is __________ at a rate of_____________?

Answer 1

The rate of change is how much the lake is changing over time.

So if in 1999 Lake Powell was 3860 Feet above Sea level and in 2007 it was 3238.4 feet above sea level

Compare by the following equation

 

X = (3238.4 - 3860) / (2007 - 1999)

 

X = -621.6 / 8 = -77.7

 

The surface elevation of Lake Powell is Decreasing at a rate of 77.7 feet per year