A proportional relationship is described by the equation
... y = k·x
The point (x, y) = (0, 0) is <em>always</em> 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 <em>for x > 10 </em>and the graph will <em>not</em> go through the origin because the function is <em>not defined</em> there.
The chance of a king and a ace being drawn out of a deck of cards would be 8 out of 52
4 + 1.3 = 5.3
5.3 - 5.7 = -.4
The temperature at 10pm was -.4°F
Correct me if I'm wrong. :)
<span>I got 18 x 18 = 324.</span>
