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 an 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.