IXL | Write equations for proportional relationships from graphs

Every spring, Jennifer plants colorful flowers in her garden. This year, she decides to plant petunias. She buys them at the garden store, brings them back home, and starts planting.

There is a proportional relationship between the amount of time (in minutes) Jennifer has been working in her garden,

and the number of petunias she has planted,

Write an equation for the relationship between x and

Simplify any fractions.

ref_doc_title.

Learn with an example

question

The Iron-It-Out laundromat dry cleans Roxanne's suits.

There is a proportional relationship between the number of suits Roxanne dry cleans,

and the total cost (in dollars),

Write an equation for the relationship between x and

Simplify any fractions.

key idea

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.

solution

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 10 dollars per suit.

The equation for the relationship is:

Looking for more? Try these:

Lesson: Proportional relationships

$Confetti$

Excellent!

Now entering the Challenge Zone—are you ready?

Teacher tools

Work it out

Not feeling ready yet? These can help:

N.4Find the constant of proportionality from a graph

N.2Write equations for proportional relationships from tables

Lesson: Proportional relationships

Excellent! You got that right!

Jumping to level 1 of 1

Excellent!