# Graphing proportional relationships example | 8th grade | Khan Academy | Summary and Q&A

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August 9, 2013
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## TL;DR

Graph a line with a proportional relationship and unit rate of 0.4. Determine the equation of the line.

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### Q: How do you determine if a relationship is proportional?

A proportional relationship can be identified if the equation is in the form y = kx, where k represents the constant of proportionality.

### Q: What does the point (0,0) signify on the graph?

The point (0,0) indicates that when there are zero x-values, there will also be zero y-values. It is a fundamental property of proportional relationships.

### Q: How can you find the slope of the graph?

The slope is determined by calculating the change in y divided by the change in x. In this case, the slope is 2/5 or 0.4.

### Q: Why is the equation of the line y = 0.4x?

The equation of a proportional relationship is y = kx, where k is the constant of proportionality. In this case, the slope of 0.4 represents the value of k.

## Summary & Key Takeaways

• To graph a proportional relationship, the point (0,0) should be on the line. As x increases by 1, y increases by 0.4.

• The point (5,2) is on the graph, indicating a change in x of 5 corresponds to a change in y of 2.

• The slope of the graph, representing the rate of change, is calculated to be 0.4. The equation of the line is y = 0.4x.