In this activity, students draw a line and determine its slope. They understand that the slope of a line is actually the ratio of rise over run.

Before the Activity

See the attached PDF file for detailed instructions for this activity

Print page 47 from the attached PDF file for your class

During the Activity

Distribute the page to the class.

Follow the Activity procedures:

Display the axes and draw a line from the third quadrant to the first quadrant, passing through the origin

Construct two points on the line in quadrant I, and label them A and C

Construct a line parallel to the x-axis through A and a line parallel to the y-axis through C

Label the point of intersection of the lines as B

Construct and measure segments AB and BC, and compute the ratio (BC)/(AB)

Understand that this ratio of change in y-coordinate to change in x-coordinate is called the slope of the line

Move A and C along the line and observe that the slope of a line remains constant at all points

Determine the equation of the line, and observe that as the line is rotated around the origin, the slope of the line is equal to the coefficient of x in the equation

Understand that the y-coordinate of a point on a line is the product of the x-coordinate and the slope

After the Activity

Review student results:

As a class, discuss questions that appeared to be more challenging