9-Jun-15Created by Mr. Lafferty Maths Dept. Simplifying Ratios Ratio Calculations Proportional...

18 Apr 202318 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.

Simplifying Ratios

Ratio Calculations

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Proportional Division

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Starter QuestionsStarter Questionsw

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18 Apr 202318 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww

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1.1. Understand the term ratio. Understand the term ratio. ..

1. To understand what a ratio is and explain how we can sometimes simplify them.

2.2. Calculate and simplify Calculate and simplify basic ratios.basic ratios.

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RatioRatioSimplifying a ratio ?

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Ratios can be used to compare different quantitiesRatios can be used to compare different quantities

Example : There are 2 triangles and 3 rectangles.

The ratio of triangles to rectangles is said to be 2 : 3

Note: The ratio of rectangles to triangles is said to be 3 : 2


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.com Simplifying a ratio is like simplifying fractionsSimplifying a ratio is like simplifying fractions

Fraction :÷2

÷2

6 6 3= =

8 8 4

Ratio : ÷2 ÷26 : 8 = 6 : 8 = 3 : 4


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Now try Ex 1&2Ch11 (page 124)

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1.1. Use tabulating method Use tabulating method to work out ratios.to work out ratios.

1. To show how to do ratio calculations.

2.2. Show appropriate Show appropriate working.working.

Ratio CalculationsS4

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Ratio Calculations

Example : The ratio of boys to girls is 4:5. If there are 16 boys, how many girls are there.

boys girls

4 5

16 20x 4 x 4

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Ratio Calculations

Example : The ratio of cars to buses is 3:7. If there are 49 buses, how many cars are there.

cars buses

3 7

21 49x 7 x 7

RatioRatio

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Now try Ex 3Ch11 (page 128)

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RatioRatioRatio Calculations



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1. Explain how to work out proportional division by using shares.

1. Work out equal number of shares for a ratio.

2. Solve problems using shares.

3. Show appropriate working.

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RatioRatioSharing Money

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the ratio 3:5. How much does each get ?

Step 1 : Since the ratio is 3:5, there are :

3+5 = 8 shares

Step 2 : Each share is worth : 50

8 400

Step 3 : Bill gets 3 x 50 = £150

Ben gets 5 x 50 = £250Check !150 + 250 = 400


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3:1. How many cakes does each get ?

Step 1 : Since the ratio is 3:1, there are :

3+1 = 4 shares

Step 2 : Each share is worth : 6

4 24

Step 3 : Ryan gets 3 x 6 = 18

Ross gets 1 x 6 = 6Check !18 + 6

= 24


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Now try Exercise 4Ch11 (page 130)

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9-Jun-15Created by Mr. Lafferty Maths Dept. Simplifying Ratios Ratio Calculations Proportional...

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