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SECOND-TERM E NOTES
WEEK ONE
DATE
CLASS
TOPIC: RATIO AND PERCENTAGE
PERIOD
DURATION: 40MINS
BEHAVIOURAL OBJECTIVES: Pupils should be able to:
- Define ratio
- Solve equal and equivalent ratio
- Change ratio to its lowest number.
Reference Materials
Lagos state scheme of work,
Online information
Relevant materials
Pupils textbook
Entry Behavior: pupils are familiar with the topic in their previous classes.
CONTENT
RATIO AND PERCENTAGE
Meaning of ratio
The relation between two quantities (both of the same units) obtained by dividing one quantity with another is called ratio. Ratio can be denoted by using the symbol ( : ).
EXAMPLE 1
What is the ratio between the weight two bags of sugar of 4kg and 6kg respectively?
Solution
Ratio of weights of bags of sugar = 4kg/ 6kg = 2/3 = 2:3
EXAMPLE 2
A pole of length 165cm is divided into two parts such that lengths are in the ration 7:8. Find the length of each part of the pole?
Total ratio = 7 + 8 = 15
First part = 7/15 , second part = 8/15
Length of first part = 7/15 of 165cm
= 7/15 × 165
= 7 x 11 = 77cm
1 x 1
Length of second part = 165cm – 77cm = 88cm
DIRECT PROPORTION
Examples
- A marker costs $18. Calculate the cost of 5 markers.
- A student went to the market to purchase textbooks. He purchased two textbooks for $24
- What is the price of one notebook?
- What would be the price of 5 such note
Solution
- If one marker = $18
5 markers = $18 x 5 = $90
- 2 textbooks = $24
1 textbook = m
2 × m = 1 x $24
2m = $24
M = $24 ÷ 2 = $12. Therefore 1 textbook = $24
(b) Since 1 textbook = $12
5 textbooks = $12 × 5 = $60
Equal and equivalent ratios
- The two ratios below are equal or equivalent.
1/2 = 4/ 8
3/5 = 6/10
- The two ratio below are not equal or equivalent
4/3≠6/10 3/5≠7/15
EVALUATION
- What is ratio?
- Find the ratio of each of the following in its lowest terms:
- 24cm: 72cm
- 425km: 750km
- 75min: 150min
- 85kg: 102kg
- A field is 50m in length and 60m in width. Find the ratio between its width and length.
- A scooter can travel 225km with 5 litres of petrol. How many litres of petrol is needed to travel 675km?
Strategies& Activities:
Step1: The teacher revises the previous topic.
Step2: The teacher introduces the new topic.
Step3: The teacher explains the new topic.
Step4: Teacher welcomes pupils’ questions.
Step5: The teacher evaluates the pupils
Assessment & Evaluation:
- Define ratio
- Solve equal and equivalent ratio
- Change ratio to its lowest number.
(WRAP-UP CONCLUSION)
The teacher goes over the topic once again to enhance better understanding
Exercise 3
Write these ratios in their lowest terms:
- 8 /6 2. 12 /10 3. 9/ 12 4. 8 /16 5. 2 /10 6. 2 /6 7. 3 15 8. 2 /20
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