Solving a Proportion Problem

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Solving a Proportion Problem
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A Ratio and a Proportion
Ratio The relationship in quantity, amount, or
size between two or more things. Typically
expressed as a quotient of two mathematical
expressions (i.e. A FRACTION). For example
Proportion An equation that equates two ratios
(i.e. TWO EQUAL FRACTIONS). For example
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Proportional

•  

Note If y 0, then x 0. Thus, all
proportional relations must contain the point
(0,0).
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Example

• Is the relation below proportional?

x 2 4 8 9
y 3 10 12 15
 
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Using a Table to solve a Proportion Question
Toby uses seven tubes of toothpaste every ten
months. How many tubes would he use in 5 years?
5 years 5x12 60 months
Months Tubes


10
7
x6
x6
60
?
42
42 Tubes
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Using an Equation to solve a Proportion Question
Toby uses seven tubes of toothpaste every ten
months. How long would it take him to use 100
tubes?
You learned this method in middle school. Can you
prove/justify that it works?
Tubes
Months
142.86 Months
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Using a Diagram to solve a Proportion Question

• One more way to organize your work for 2-99

1.8
15
x 1.8
0x
7.83
6
y
27
20
14.1
10.8
36
x 1.8