3. Example: In a class there are 14 boys and 21 girls
Compare between boys and girls
1) No. of boys less than No. of girls
2) No. of girls greater than No. of boys
The ratio: Is a method to compare between two
numbers or two quantities by division.
The ratio between two numbers = First number
Second
4. 1) Ratio between boys and girls =
2) Ratio between girls and boys =
1
5
25
÷5
÷5
=
3
5
2
5
15
÷5
÷5
Ratio
=
5
3
Ratio
5. Ex(1) : Using the opposite figure
Write the ratio between :
6
3
(1) Circles and triangles =
÷3
÷3 2
1
3
6
(2) Triangles and circles
=
÷3
÷3 1
2
6
3
3
(3) Circles and whole shapes
=
÷3
÷3
9
3
3
1
2
6. Expressing the ratio
The ratio between two numbers 3 and 7
7
3 7
:
3
7
:
3
Anteceden
t
Consequent
First term Second term
Note
: 7
:
3 3
:
7
≠
=
Fraction
form
Pole
form
7. Ex(3) There are 5 fish and 6 birds
Write the ratio between :
(1) Birds and Fish =
(2) Fish and birds =
(3) Fish and all animals =
(4) Birds and all animals =
5
6
6
5
11
5
11
6
= 6 :
5
= 5 :
6
= 5 :
11
= 6 :
8. Ex(4) : The number of pupils in a school is 480 ,
If the number of boys is 320 Find :
1) Ratio between boys and girls =
2) Ratio between girls and boys =
3) Ratio between boys and all pupils =
• [ Try by
yourself ]
