Learning goals: Teacher Facing Generalize a process for finding missing values in a proportional relationship, and justify (orally) why this can be abstracted as $y=kx$, where $k$ is the constant of proportionality. Generate an equation of the form $y=kx$ to represent a proportional relationship in a familiar context. Write the constant of proportionality to complete a row in the table of a proportional relationship where the value for the first quantity is 1. Full lesson plan (warm-up, activities, synthesis, cool-down prompt) from 7.2 Introducing Proportional Relationships, Grade 7.