Finding k Using Slope

Finding k Using Slope

Introduction

In proportional relationships, the constant of proportionality, k, describes how one quantity changes compared to another. This constant can also be understood as the slope of a graph.

Imagine a boy earns $3 for every newspaper route he delivers. If he delivers 1 route, he earns $3. If he delivers 4 routes, he earns $12.

When we graph this situation, the points lie on a straight line passing through the origin. Because the graph is a straight line through the origin and the money earned increases at a constant rate, this...