Graphs and Proportional Relationships

Lesson 2.5:

Graphing Proportional Relationships

Definition:

Proportional Graph: A proportional graph looks like a straight line going through the origin (0,0) and can be represented by the equation y = kx.

Which graph represents a proportional relationship?

Multiple Choice

Is this a proportional graph?

• Yes

• No

Multiple Choice

Is this a proportional graph?

• Yes

• No

Graph the equation y = 2x

x

y

Decide which graph is proportional:

The graph shows a proportional relationship between the
cups of flour a baker uses and the number of cookies
made.

●What does the point (0,0) represent?

●What does the point (1,18) represent?

Multiple Choice

This graph relates water use in gallons compared to the minutes that pass. What does the point (2,10) represent?

• 2 gallons of water used in 10 minutes

• 10 gallons of water used in 2 minutes

• 5 gallons of water used in 1 minute

• 1 gallon of water used in 5 minutes

Use the graph to create an equation:

Multiple Choice

Write an equation for this graph.

• y = 6x

• y = $$\frac{1}{6}x$$

• y = 12x

• y = $$\frac{2}{12}x$$

​Conclusion: Write two complete sentences about what you know.