Ratios Proportions Percents

Ratios Proportions Percents

A ratio is a way to compare two or more numbers

Ratios can be written as:1). 2 numbers separated by a colon :

2). A fraction

3). With the word “to”

Ratios

ratiorate

rationrationalunit rate

RatiosRatios look like

fractions because they are fractions

= 1/61 : 2=

Types of Ratio ComparisonsPart to Part

The ratio of strawberries to oranges is 2 to 3.

The ratio of oranges to strawberries is 3 to 2.

Types of Ratio ComparisonsPart to Whole

The ratio of kittens to total pets

is 3 to 8.The ratio of puppies to all pets

is 5 to 8.

Ratio of squares to circles is 3/6Ratio of squares to circles is 3 to 6Ratio of squares to circles is 3:6

Ratio of squares to total figures is 3:10

Ratio of circles to total figures is 6/10

Ratio Examples

Part to

Part

Part to

Whole

ProportionsProportions are two equivalent

ratios,written as Part to Whole

1/2 2/4 3/6 4/8= = =

As one number or shape increases, the other number or shape increases by the same ratio

1/2 2/4 3/6 4/8

proportional

ProportionsTesting Proportions to see if they

are equivalent

26

39

1818Cross Multiply to see if they are equal

If they are the same, they are

equivalent AND

proportional!Use cross multiplication to test

proportions if you are given 2 fractions (or more)

ProportionsSolving a proportion when you only

have some information

Find the unknown number.Step 1:

26

x9=

L oo k

Proportions26

L k at the number directly above or below the unknown

number.

x9

Step 2:

=

Circle this number.

Proportions

L k at the number directly across from the circle

L oo kStep 3:

Draw a square around this number.

x9=2

6

Proportions26

Draw a triangle around the number above or below the

square.

x9

Step 4:

=

Proportions26

x9

Step 5: Fill in the template and solve

=

* = x = x9 6 2

x = 3*

Proportions26

x9

Solving using backtracking:

=

Step 1: Cross multiply

2 9 = 6 x* *18 = 6x

Proportions26

x9

Solving using backtracking:

=

Step 2: Tell the “story” of x

x6*

18

Proportions26

x9

Solving using backtracking:

=

Step 3: Backtrack!

x6*

186x = 3

Percents

Percent means parts per 100,and tells you a ratio "out of 100"

So 50% means 50 per 100

Ratios Proportions Percents

Ratios can be written as:1) 2 separated

with a ( : )

2) A

3) with the word

ratio of to is 3/6ratio of to is 3 to 6ratio of to is 3:6

Proportions are two equivalent ratios.

A is a way to compare or

more numbers.Proportions are written as p a r t to w h o le.

Ratio of squares to total figures is

When given 2 proportions:

When solving for an unknown:

Percent means parts per 100, and tells you a ratio "out of 100"

Ratios