When interpreting graphs of real world situations, what can the slope of each part tell you about the situation

When interpreting graphs of real world situations, the slope of each part tell you the average rate of change (increase or decrease) of the dependent variable with respect to the independent variable. This is, how much the dependent variable increased (or decrease) per each unit the independent varaible increased, in average.

slope = change in independent variable / change in dependent variable

slope = Δy / Δx