S4_General_Ratio_TJ_Chapter11

S4_General_Ratio_TJ_Chapter11 - Ratio S4 Simplifying Ratios

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Unformatted text preview: Ratio S4 Simplifying Ratios www.mathsrevision.com Ratio Calculations Proportional Division 13 Feb 2012 Created by Mr. Lafferty Maths Dept. Starter Questions S4 www.mathsrevision.com 13 Feb 2012 Created by Mr. Lafferty Maths Dept. Ratio S4 Simplifying a ratio ? Learning Intention Success Criteria 1. Understand the term ratio. . 2. Calculate and simplify basic ratios. www.mathsrevision.com 1. To understand what a ratio is and explain how we can sometimes simplify them. 13 Feb 2012 Created by Mr. Lafferty Maths Dept. Ratio S4 Simplifying a ratio ? Ratios can be used to compare different quantities www.mathsrevision.com 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 13 Feb 2012 Created by Mr. Lafferty Maths Dept. Ratio S4 Simplifying a ratio ? Simplifying a ratio is like simplifying fractions www.mathsrevision.com Fraction : 6 6 3 = 2 = 8 8 4 2 Ratio : 6 : 8 = 6 : 8 = 3 : 4 2 2 13 Feb 2012 Created by Mr. Lafferty Maths Dept. Ratio S4 Simplifying a ratio ? www.mathsrevision.com Now try Ex 1&2 Ch11 (page 124) 13 Feb 2012 Created by Mr. Lafferty Maths Dept. Starter Questions S4 www.mathsrevision.com 13 Feb 2012 Created by Mr. Lafferty Maths Dept. S4 Ratio Calculations Learning Intention Success Criteria 1. Use tabulating method to work out ratios. 2. Show appropriate working. Ratio www.mathsrevision.com 1. To show how to do ratio calculations. 13 Feb 2012 Created by Mr. Lafferty Maths Dept. S4 Ratio Calculations Example : The ratio of boys to girls is 4:5. If there are 16 boys, how many girls are there. boys x 4 4 16 girls 5 20 x 4 Ratio www.mathsrevision.com 13 Feb 2012 Created by Mr. Lafferty Maths Dept. S4 Ratio Calculations Example : The ratio of cars to buses is 3:7. If there are 49 buses, how many cars are there. cars x 7 3 21 buses 7 49 x 7 Ratio www.mathsrevision.com 13 Feb 2012 Created by Mr. Lafferty Maths Dept. S4 Ratio Calculations Ratio www.mathsrevision.com Now try Ex 3 Ch11 (page 128) 13 Feb 2012 Created by Mr. Lafferty Maths Dept. Starter Questions S4 www.mathsrevision.com 13 Feb 2012 Created by Mr. Lafferty Maths Dept. S4 Sharing Money Learning Intention Success Criteria 1. Work out equal number of shares for a ratio. 2. Solve problems using shares. 3. Show appropriate working. Ratio www.mathsrevision.com 1. Explain how to work out proportional division by using shares. 13 Feb 2012 Created by Mr. Lafferty Maths Dept. S4 Sharing Money Example : Bill and Ben share a raffle win of 400 in the ratio 3:5. How much does each get ? Ratio www.mathsrevision.com Step 1 : Since the ratio is 3:5, there are : 3+5 = 8 shares Step 2 : Each share is worth : Step 3 : Bill gets 3 x 50 = 150 Ben gets 5 x 50 = 250 13 Feb 2012 Created by Mr. Lafferty Maths Dept. 50 8 400 Check ! 150 + 250 = 400 S4 Sharing Money Example : Ryan and Ross share 24 cakes in the ratio 3:1. How many cakes does each get ? Ratio www.mathsrevision.com Step 1 : Since the ratio is 3:1, there are : 3+1 = 4 shares Step 2 : Each share is worth : Step 3 : Ryan gets 3 x 6 = 18 Ross gets 1 x 6 = 6 13 Feb 2012 Created by Mr. Lafferty Maths Dept. 6 4 24 Check ! 18 + 6 = 24 S4 Sharing Money Ratio www.mathsrevision.com Now try Exercise 4 Ch11 (page 130) 13 Feb 2012 Created by Mr. Lafferty Maths Dept. ...
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