IXL | Write equations for proportional relationships from graphs

Dakota has written her own recipe for pot roast.

There is a proportional relationship between the weight (in pounds) of the pot roast,

and the total cooking time (in hours),

Write an equation for the relationship between x and

Simplify any fractions.

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Learn with an example

Irma wants to save up some money to buy a new smartphone, so she babysits on the weekends.

There is a proportional relationship between the time Irma spends babysitting (in hours),

and the amount of money she earns babysitting (in dollars),

Write an equation for the relationship between x and

Simplify any fractions.

The graph of a proportional relationship is a straight line passing through the origin

(

)

A proportional relationship between x and y can be modeled by the equation

The letter k is the constant ratio of y to

It is called the constant of proportionality.

To write an equation for the relationship between x and

first find the constant of proportionality. Start by identifying the coordinates of one of the points on the line.

Calculate the ratio of the

y-coordinate

to the

x-coordinate.

The constant of proportionality is 8 dollars per hour.

The equation for the relationship is:

Looking for more? Try these:

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