Lesson 1

A formula can be used to determine the slope of any line, as long as the coordinates of at least two points on the line are known. Search the Internet using the keywords “Montgomery County Slope of a Line.” Watch the Math Dude video, “Slope of a Line,” from start to finish. The video is a great review of what you learned about slope in Grade 11 and will introduce you to a new slope formula.

When you know two points with coordinates (x1, y1) and (x2, y2) on a line, you can determine its slope, m, by using the following formula:

Study and review the following examples and solutions in the textbook:

• “Example 1” (Rain Barrels) on page 15
• “Example 2” (Banquet Hall) on page 18

Try This 4

Kole sells used cars on the Auto Mile in Wetaskiwin, Alberta. The graph shows his remuneration, or amount of pay, versus his sales for the month of July.

1. What does the point (0, 1200) represent?             
2. What does the point (80 000, 4400) represent?    
3. Using the slope formula, , calculate the slope of this line.
   

Save your responses in your course folder.

Share 3

With a partner or in a group, discuss the following question:

• The slope of the line in Try This 4 is a decimal. Convert the decimal to a percent, and explain the meaning of the percent in relation to the question.

Save your summarized response in your course folder.