IXL | Graph proportional relationships and find the slope

Max is finding the perimeter of different-sized equilateral triangles. He finds the perimeter is always 3 times longer than the side length.

There is a proportional relationship between the side length of the equilateral triangle in

feet,

and the perimeter of the equilateral triangle in

feet,

Graph this relationship. Select two points to draw a line.

x-axis, Side length in feet, y-axis, Perimeter in feet. Coordinate plane graph with 1 quadrants, x-axis coordinates from 0 to 10, y-axis coordinates from 0 to 10.

What is the slope of the line?

ref_doc_title.

Learn with an example

question

Patty loves to play the piano but doesn't like practicing the exercises her piano teacher assigns. Patty knows the exercises will help her play better though, so she tries to motivate herself using her favorite treat — chocolate chip cookies. Patty gives herself 2 cookies for every hour he practices.

There is a proportional relationship between the amount of time (in

hours)

that Patty practices the piano,

and how many cookies she gives herself,

Graph this relationship. Select two points to draw a line.

What is the slope of the line?

key idea

The graph of a proportional relationship between

and

is a straight line passing through the origin

(

)

The slope of this line is equal to the unit rate of

solution

To graph the relationship, find two points that satisfy it and draw a line through them.

Since the relationship is proportional, the line passes through the point

(

)

In other words, if Patty doesn't practice the piano (0 hours), then she will get 0 cookies.

To find another point, look for clues in the problem that describe the unit rate.

2 cookies per hour is the unit rate for this relationship. Each time Patty practices for 1 more hour, she gives herself 2 more cookies.

From

(

)

move 1 to the right and 2 up to plot

(

)

The line through

(

)

and

(

)

shows the proportional relationship.

The unit rate is 2 cookies per hour. So, the slope of the line is 2.

Looking for more? Try these:

Lesson: Proportional relationships

Lesson: Slope

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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.8Complete a table and graph a proportional relationship

Lesson: Proportional relationships

Lesson: Slope

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