The consistent relationship between two quantities that change is called the rate of change. This concept is commonly visualized on a graph, where a line’s steepness represents this rate. The slope of a line is a numerical representation of this steepness, indicating how much the dependent variable changes for every unit change in the independent variable. For instance, if a car travels 100 miles in 2 hours, the rate of change (average speed) is 50 miles per hour, and this would be reflected as the slope on a distance-time graph.
Understanding and calculating this ratio is fundamental to many fields, including mathematics, physics, economics, and engineering. It allows for the prediction of future values based on observed trends, optimization of processes, and the analysis of dynamic systems. Historically, the formalization of this concept emerged from the development of calculus and analytic geometry, enabling more precise quantitative analysis of change.