11 Apr 202311 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.

Simplifying Ratios

Ratio Calculations

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11 Apr 202311 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.

Starter QuestionsStarter Questionsw

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2. Calculate 20% of 220

(a) 123 (b) 202 (c) 0.09

1. 3x + 5 = 17

3. How many significant numbers

4. Car depreciates by 20% in its first year. I f it was bought new for £10 000. How much is it worth now.

MNU 3-08a MNU 4-08a

11 Apr 202311 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. We are learning what a ratio.

RatiosRatios

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

What is a ratio ?MNU 3-08a MNU 4-08a

11 Apr 202311 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww

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RatiosRatios

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

What is a ratio ?

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

MNU 3-08a MNU 4-08a

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RatiosRatios

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

Simplifying a ratio ?

Fraction :÷2

÷2

6 6 3= =

8 8 4

Ratio : ÷2 ÷26 : 8 = 6 : 8 = 3 : 4

MNU 3-08a MNU 4-08a

11 Apr 202311 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.

Now try Exercise 1&2

Ch15 (page 175)

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RatiosRatiosSimplifying a ratio ?MNU 3-08a

MNU 4-08a

11 Apr 202311 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.

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2. Find the rule connecting a and b.

1230

(a) 0.13 (b) 0.02 (c) 1.09

1. 3x + 5 = 17

3. Round to 1 decimal place

4. Simplify fraction

1 432a

3 15

11

7b

MNU 3-08a MNU 4-08a

11 Apr 202311 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.ww

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.com Learning IntentionLearning Intention Success CriteriaSuccess Criteria

1.1. Apply tabular method to Apply tabular method to solve problems involving solve problems involving ratios.ratios.

1 We are learning how to do ratio calculations.

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2.2. Show appropriate Show appropriate working.working.

Ratio CalculationsMNU 3-08a MNU 4-08a

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RatiosRatiosRatio 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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RatiosRatiosRatio 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

MNU 3-08a MNU 4-08a

11 Apr 202311 Apr 2023 Created by Mr. Lafferty Maths Dept.Created by Mr. Lafferty Maths Dept.

Now try Exercise 3Ch15 (page 179)

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RatiosRatiosRatio CalculationsMNU 3-08a

MNU 4-08a