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For example, Let's say I am graphing a proportional relationship even If it doesn't go through origin and it is an equivalent ratios, Is it proportional or does it have to go throught the origin to be proportional?

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A proportional relationship is described by the equation

... y = k·x

The point (x, y) = (0, 0) is always a solution to this equation.

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In short, if the relationship is proportional, its graph will go through the origin. If the graph does not go through the origin, the relationship is not proportional.

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Note that this is true if the domain includes the origin. You can have y = kx for x > 10 and the graph will not go through the origin because the function is not defined there.

User Tammoi
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