Lesson Plan: Types of Slope

Lesson Objectives

• Identify positive, negative, zero, and undefined slopes
• Relate slope types to real-world situations
• Graph lines with different slope types

TEKS Standards

• 8.4B: Graph proportional relationships, interpreting unit rate as slope.
• 8.4C: Use data to determine rate of change or slope and y-intercept.
• 8.5I: Write linear equations using various representations.
• A.3C: Graph linear functions and identify key features.

Prerequisite Skills

• Familiarity with the coordinate plane and plotting points
• Understanding of the concept of slope as the ratio of the vertical change (rise) to the horizontal change (run) between two points
• Experience with using interactive graphing tools or online resources (a Desmos activity is provided in this lesson)

Engage (5 minutes)

1. Use these math clip art pieces to show different types of slopes: https://www.media4math.com/library/75389/asset-preview
2. Ask students to observe the directions of the lines and describe what they notice about the slopes.
3. Encourage students to share their observations and discuss the differences in line directions.

Explore (15 minutes)

1. Play the following video, which describes the different types of slopes: https://www.media4math.com/library/75390/asset-preview
2. Review the following vocabulary terms:
   • Positive Slope: https://www.media4math.com/library/42968/asset-preview
   • Negative Slope: https://www.media4math.com/library/42969/asset-preview
   • Zero Slope: https://www.media4math.com/library/42970/asset-preview
   • Undefined Slope: https://www.media4math.com/library/42970/asset-preview
3. Have students use this Desmos activity: https://www.media4math.com/library/75388/asset-preview. Students can change the slope of the line in two ways:
   • Clicking and dragging on one of the points
   • Changing the values for a, b, c, and d to modify the coordinates.
4. Have students use the Desmos activity to show examples of these types of slopes:
   • Positive Slope
   • Negative Slope
   • Zero Slope
   • Undefined Slope

Evaluate (10 minutes)

1. Facilitate a class discussion by asking students to share their observations and findings from the previous activity.
2. Address any misconceptions or clarify any confusions that may arise.
3. Provide individual practice problems or a short quiz to reinforce the concepts of positive, negative, zero, and undefined slopes.

Quiz

1. What type of slope does a line have if it is slanting upwards from left to right?
   A. Positive slope
   B. Negative slope
   C. Zero slope
   D. Undefined slope
   
    
2. If a line is horizontal, what is its slope?
   A. Positive slope
   B. Negative slope
   C. Zero slope
   D. Undefined slope
   
    
3. A vertical line has what type of slope?
   A. Positive slope
   B. Negative slope
   C. Zero slope
   D. Undefined slope
   
    
4. Which type of slope would a line have if it is slanting downwards from left to right?
   A. Positive slope
   B. Negative slope
   C. Zero slope
   D. Undefined slope
   
    
5. If the slope of a line is 0, what can you say about its direction?
   A. It is slanting upwards
   B. It is slanting downwards
   C. It is a horizontal line
   D. It is a vertical line
   
    

Answers Key

1. A

2. C

3. D

4. B

5. C

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