Transcript Proportional and Nonproportional Relationships

7th Grade Math
Lesson Objective:
Students will identify proportional and
nonproportional relationships.
Vocabulary
 Proportional
 Two quantities that have a constant ratio
 Example: 8 16
16 = 16
1 2
 Nonproportional
 Two quantities that do NOT have a constant
ratio
 Example: 10 17
17 ≠ 20
1 2
Identifying Proportional
Relationships

Ms. Cochran is planning a year-end pizza
party for her students. Ace Pizza offers
free delivery and charges $8 for each
medium pizza. Is the cost of an order
proportional to the number of pizzas
ordered?
cost of order
# of pizzas
8
1
16
2
16 = 16
Yes
Identifying Proportional
Relationships

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?
cost of order 10
# of pizzas 1
17
2
17 ≠ 20
No
Identifying Proportional
Relationships

At the beginning of the school year, Isabel
had $120 in the bank. Each week, she
deposits another $20. Is her account
balance proportional to the number of
weeks since she started school?
account balance 120 140
week of school 1
2
140≠ 240
No
Identifying Proportional
Relationships

A recipe for jelly frosting calls for 1/3 cup
of jelly and 1 egg white. Is the number of
egg whites used proportional to the cups
of jelly used?
# of egg whites
cups of jelly
1
2
2/3= 2/3
1
3
2
3
Yes