Graphing Proportional Relationships Practice

Question

Complete this assessment to review what you've learned. It will not count toward your grade.
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Question
Use the image to answer the question.

An illustration shows a coordinate plane with 4 quadrants. The x-axis ranges from negative 9 to 9 in one unit increments, and the y-axis ranges from negative 11 to 11 in one unit increments. A line is graphed on the plane. An upward slanting line passes through points plotted at left parenthesis 3 comma 1 right parenthesis, left parenthesis 6 comma 2 right parenthesis, and left parenthesis 9 comma 3 right parenthesis.

Write the equation of the line y=mx through the origin that describes the proportional relationship shown in the graph.

Answer 1

To find the slope (m) of the line, we can use two points on the line such as (3,1) and (6,2):

m = (y2 - y1) / (x2 - x1)
m = (2 - 1) / (6 - 3)
m = 1 / 3

Now that we have the slope, we can write the equation of the line in slope-intercept form:
y = mx

So, the equation of the line y = (1/3)x describes the proportional relationship shown in the graph.