7th Grade Math

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Proportions

PART A B C DE

Multi-Part

Lesson 1

GLE 0706.2.3

Develop an understanding

of and apply proportionality.

SPI 0706.1.3 Recognize

whether information given

in a table, graph, or

formula suggests a directly

proportional, linear,

inversely proportional, or

other nonlinear relationship.

Also addresses GLE 0706.2.4,

SPI 0706.2.7.

272 Proportions and Similarity

Proportional and

Nonproportional Relationships

PIZZA Ms. Cochran is planning

a year-end pizza party for her

students. Ace Pizza offers free

delivery and charges $8 for

each medium pizza.

1. Copy and complete the table to
   determine the cost for different
   numbers of pizzas ordered.

Cost ($)

Pizzas Ordered

8

1234

2. For each number of pizzas, write the relationship of the cost and
   number of pizzas as a ratio in simplest form. What do you notice?

Two quantities are proportional if they have a constant ratio. For

relationships in which this ratio is not constant, the two quantities are

nonproportional.

__cost of order

pizzas ordered

= _^8

1

= _^16

2

= _^24

3

= _^32

4

or $8 per pizza

The cost of an order is proportional to the number of pizzas ordered.

Identify Proportional Relationships

PIZZA Uptown Pizzeria sells medium pizzas for $7 each but

charges a $3 delivery fee per order. Is the cost of an order

proportional to the number of pizzas ordered? Explain.

Cost ($) 10 17 24 31

Pizzas Ordered 1234

For each number of pizzas, write the relationship of the cost and

number of pizzas as a ratio in simplest form.

__pizzas orderedcost of order _^10

1

or 10 _^17

2

or 8.5 _^24

3

or 8 _^31

4

or 7.75

Since the ratios of the two quantities are not the same, the cost of

an order is not proportional to the number of pizzas ordered.

Main Idea

Identify proportional

and nonproportional

relationships.

Vocabulary

proportional

nonproportional

V

p

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