Unit 5, Lesson 8
Slopes Don't Have to Be Positive
Accelerated 7
Preparation
Lesson Narrative
In this lesson, students are introduced to lines with non-positive slopes. Students begin by reflecting on similarities and differences between lines that slope in different directions. Then they are introduced to the context of a fare card with decreasing funds. They graph this relationship and see that the line appears to be going “downhill” from left to right and reason that it makes sense for the slope to be negative in terms of the context (MP2).
Students are then introduced to a related context of a fare card but with a constant balance. They interpret a graph of this situation and reason that it makes sense that a flat graph has a slope of zero.
- Create a graph of a line representing a linear relationship with a non-positive rate of change.
- Interpret the slope of a non-increasing line in context.
Let’s find out what a negative slope means.
Required Materials
Activity 2
Required Preparation
For the digital version of the activity, acquire devices that can run the applet.