Compare proportional and non-proportional relationships.
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This lesson is a good opportunity for students to construct arguments and defend their decisions around if a relationship is proportional or not. They may also work in pairs to listen to and critique the arguments of others (MP.3).
If you need to adapt or shorten this lesson for remote learning, we suggest prioritizing Anchor Problem 1 (benefits from discussion) and Anchor Problem 3 (benefits from worked example). Find more guidance on adapting our math curriculum for remote learning here.
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Syrus is 12 years old and has a younger sister, Samira, who is 6 years old. Syrus says, “Our ages are in a proportional relationship because I am two times as old as my sister.”
Is Syrus correct? Justify your answer.
At the zoo, you can buy tickets to take a train ride between exhibits. Each ticket costs $0.50; however, there is a deal that if you buy 10 tickets, you only pay $4.00.
Is the cost of the tickets proportional to the number of tickets you buy? Create a table with some values and plot the points on a coordinate plane.
Four tables and four graphs are shown below. Which tables and graphs represent proportional relationships? Explain your reasoning for each one.
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The following resources include problems and activities aligned to the objective of the lesson that can be used to create your own problem set.
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Two ice cream shops are located across the street from one another on a busy street.
At which ice cream shop is the cost of the sundaes (including the toppings), proportional to the number of sundaes purchased? Justify your answer with tables, graphs, or an explanation.
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