Solving Proportions

A proportion is an equation stating that two ratios are equal (two equivalent fractions)

2 sextos 0

Finding the missing value in a proportion means finding the missing value for two equivalent fractions.

There are three ways to solve proportions

Method 1: Vertical

2 sextos 1Since 2 x 3 = 6, then 10 x 3 = 30. So the missing value is 30.

Method 2: Horizontal

 2 sextos 2Since 2 x 5 = 10, then 6 x 5 = 30. So the missing value is 30.

Method 3: Cross-products

2 sextos 3

Cross multiply and solve for X.

The missing value is 30.

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Solving Proportions by Cross Multiplication

In a proportional relationship such as

cross

 

 

 

we can multiply the numerator of each side by the denominator of the other side.

crossmul

 

 

The cross products of a proportion are equal. This property help us solve for an unknown value.

Solving proportions worksheets with an unknown variable  (using only integers):

Proportions

What is a Proportion

Means Extreme Property

Finding X in a Proportion 1

Finding X in a Proportion 2

Finding X in a Proportion 3

Finding X in a Proportion 4

Finding the Missing Denominator

Finding the Missing Numerator

MKY2

 

 

PP10      Proportion_I1

PP11      Proportion_I2

PP12      Proportion_I3

PP13      Proportion_I4

PP14      Proportion_I5

PP15      Proportion_I6

PP16      Proportion_I7

PP17      Proportion_I8

PP18      Proportion_I9

PP19      Proportion_I10

 

 

Solving proportions worksheets with an unknown variable  (with one decimal):

MKY2

 

 

 

 

PP20      Proportion_D1

PP21      Proportion_D2

PP22      Proportion_D3

PP23      Proportion_D4

PP24      Proportion_D5

PP25      Proportion_D6

PP26      Proportion_D7

PP27      Proportion_D8

PP28      Proportion_D9

PP29      Proportion_D10

PP30      Proportion_D11

PP31      Proportion_D12

If one term of a proportion is not known, we can use cross multiplication to find its value.

Ratio and Proportion Vocabulary