This Problem Set is a part of the Lesson 10, Unit 2, Grade 7. Introducing Graphs of Proportional Relationships This lesson introduces an important way of representing a proportional relationship: its graph. Understand that a proportional relationship can be represented in the coordinate plane by a line that includes the origin, or a collection of points that lie on such a line. Understand that a proportional relationship can be represented in the coordinate plane by a line that includes the origin, or a collection of points that lie on such a line.