Lesson 11

In the previous lesson students learned that the graph of a proportional relationship lies on a line through the origin. (Students should come to use and understand “the origin” to mean \((0,0)\).) In this lesson, they start to make connections between the graph and the context modeled by the proportional relationship, and between the graph and the equation for the proportional relationship. Given a graph, they think about what situation it might represent and learn the importance of being precise about saying which quantities are represented on each axis (MP6). They interpret the meaning of the point \((1,k)\) on the graph both in term of the constant of proportionality \(k\) in the equation \(y = kx\) and in terms of a constant rate in the context.