# How do you find the average rate of change of a function from graph?

Graphically speaking, the average rate of change of a function $f$ on the interval $\left[a , b\right]$ is represented by the slope of the secant line passing through $\left(a , f \left(a\right)\right)$ and $\left(b , f \left(b\right)\right)$. So, if you have some way of finding the slope of the secant line, then that is the average rate of change you are looking for.