Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Bellringer
1) A number that can be written as a quotient of two integers is a _________ number.
2) Compare. Use <, >, or =.
3
4
a)
c) 2
3
___
___
­5
8
11
15
b) 3
___
12
28
___
­1
12
7
d) ­1
6
Jul 26­12:38 PM
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Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Check Your Homework
Jun 6­7:28 PM
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Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Unit 3
Chapter 4 Section 3
Proportions
Objective: To test whether ratios form a proportion by using equivalent
ratios and cross products
Proportion: an equation stating that two ratios are equal
Example:
4
1
=
2 8
Cross Products: the two products found by multiplying the denominator of
each ratio by the numerator of the other ratio.
Example:
6
8
=
9
12
.
.
6 12 = 9 8
If two ratios have equal cross products, they form a proportion.
Jun 6­8:17 PM
3
Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Examples:
Writing Ratios in Simplest Form
1) Determine whether the ratios can form a proportion by writing ratios in simplest form.
a) c)
1
2
,
14
28
10 , 25
24 60
b)
10 , 40
12 56
d)
18 , 4.8
12 3.6
Using Cross Products
2) Determine whether the ratios can form a proportion using cross products.
a) 5 , 30
9 54
b)
­7 , ­55
8 65
c)
3 , 6
8 16
d)
20 , 60
1.5 4.5
Jun 10­10:28 AM
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Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Check Your Understanding:
Pg 139, #'s 1­9
Jun 10­11:04 AM
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Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Guided Problem Solving
Jun 10­11:04 AM
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Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Classwork (Partners)
Textbook Pages 139 & 140, #'s 10 - 46 even
Jun 10­11:05 AM
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Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Challenge
1) An astronaut who weighs 174 lbs on Earth weighs 29
lbs on the moon. If you weigh 102 lbs on Earth, would
you weigh 17 lb on the moon? Explain.
2) Determine whether 4n and 12n always, sometimes
9
3
or never form a proportion. Explain.
Jun 26­1:46 PM
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Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Dec 7­8:36 AM
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Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Closure
1) What is a proportion?
2) What are two methods for determining whether a pair of ratios can form a proportion.
3) Determine whether the ratios can form a proportion.
a) 12 , 16
12
9
b) 30 , 45
16 12
Jun 10­11:18 AM
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Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Homework
Practice Worksheet 4­3
Jun 10­11:25 AM
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Unit 3 Chapter 4 Section 3 Proportions.notebook
December 08, 2015
Activity Lab with Partners
Pg. 142, #'s 1-3
Jul 2­2:25 PM
12