Direct Variation

​Direct Variation

Another way of describing a relationship between X and Y that is proportional.

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One variable will always be a constant multiple of the other.​

​

y = kx​

​Constant of Proportionality

​Constant of proportionality is also known as constant of variation.​

Situations that vary directly can always be represented with the equations:

*y = Kx (K is your CoP)

*K = y/x​

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to find K you must divide Y by X

Open Ended

If x=3 and y=6, then k=.....

What would you equation be?

y=....

Open Ended

If x=2 and y=15 then k=.....

What would you equation be?

y=....

Fill in the Blanks

If x is -3 and y is 18, then

k =

Fill in the Blanks

If x is 2/3 and y is 24, then

k=

Fill in the Blanks

If x is 3 and y is -39, then

k=

Fill in the Blanks

What is the equation for the given relationship in the table?

Multiple Choice

 If x = 10.5 and y = 21, what is the equation that represents the direct variation?

• y = -2x

• y = 2x

• y = 0.5x

• y = 1.5x

• y = 2/3x

Multiple Choice

If x= 20/3 and y = 10, what is the equation that represents the direct variation?

• y = -2x

• y = 2x

• y = 0.5x

• y = 1.5x

• y = 2/3x

Multiple Choice

If x= -14 and y = 28, what is the equation that represents the direct variation?

• y = -2x

• y = 2x

• y = 0.5x

• y = 1.5x

• y = 2/3x