Answer/ Step-by-step explanation:
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Proportional relationships are relationships between two variables where their ratios are equivalent.
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Lets take a look at example one attached image:
The constant of proportionality is the value of y when x = 1 in a proportional relationship.
On which line does y = 1/2 when x = 1?
Only line C has a y- value less than 1 when x = 1, but how can we be sure that the constant of proportionality is exactly 1/2?
If the constant of proportionality of a proportional relationship is 1/2 then:
y = 1/2x (like rise over run (slope), rise up 1 unit, and run right 2 units)
We can try the point (2, 1), and plug in the values into the equation, where x = 2, y = 1.
(1) = 1/2(2)
1 = 1
Line C has a constant proportionality of 1/2 between x and y.
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Example 2, 3, and 4 is a worked out example on khan academy (attached images)