1. Ratios introduction

2. RATIOS A ratio is the comparison of two quantities with the same unit.
Ratio of a and b is written as
Ratio can be written as fraction
Ration can also be written in words
a : b
a to b
Note: ratios are “unitless” (no units)

3. Example 1: What is the ratio of cats to mice?
Number of Cats: 3
Number of Mice: 5
Ratio of cats to mice :
3:5
Ratio as a fraction :
3 to 5
Ratio in words :

4. Example 2: What is the ratio of circles to triangles?
Number of Circle: 4 8
Number of Triangle:
Ratio of circle to triangle :
4:8
Ratio as a fraction :
4 to 8
Ratio in words :

5. Example 3: Give each ratio in three forms
6 roses out of 21 flowers
Solution
Ratio form
Fractional form
In words
6 : 21
6 to 21
Example4: Give each ratio in three forms
3 dogs out of 12 animals
Solution
Ratio form
Fractional form
In words
3 : 12
3 to 12

6. Example5:. There are 300 computers and 1200 students in our school
Example5: There are 300 computers and 1200 students in our school. What is the ratio of computers to students?
Solution
Given : Number of computer = 300
Number of students = 1200
Ratio of computer to students:
300 : 1200
Ratio as a fraction :
Ratio in words :
300 to 1200

7. Try These Give the following ratios in three forms:
5 blue marbles to 9 red marbles
11 squares to 15 rectangles
12 boys to 24 girls