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Learn: Ratio and Proportion
iGCSE Mathematics
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Welcome!Today we'll learn about Ratio and Proportion. This topic is important for solving problems involving comparisons and relationships between quantities.
What is a Ratio?A ratio compares quantities of the same type, showing how much of one thing exists compared to another. It is often written as two numbers separated by a colon, like 3:2.
What is Proportion?A proportion is an equation that states two ratios are equal. For example, if 1:2 is the same as 2:4, we say they are in proportion.
Quick check: Which of the following is a correct example of a ratio?
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Simplifying RatiosTo simplify a ratio, divide both numbers by their highest common factor (HCF). For example, 12:16 simplifies to 3:4 by dividing by 4.
To simplify the ratio 18:24, divide both numbers by {{blank0}}, resulting in {{blank1}}.
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Dividing a Quantity in a Given RatioTo divide a quantity in a given ratio, add the parts of the ratio to find the total and allocate the quantity accordingly. For example, dividing £60 in the ratio 2:3 means £60 ÷ (2+3) = £12 per part. Then, 2 parts = £24 and 3 parts = £36.
Match the items on the left with their correct pairs on the right
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Using Ratios to Find UnknownsWhen ratios are proportional, you can find unknowns by scaling. For example, if 4:6 is proportional to x:15, solve by cross-multiplication: 4 × 15 = 6 × x, so x = 10.
Match the items on the left with their correct pairs on the right
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Review Time!Great work! You've learned about Ratios and Proportions. Let's test your understanding with some final questions.
Which statements about ratios are true? (Select all that apply)
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Match the items on the left with their correct pairs on the right
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If £120 is divided in the ratio 5:7, how much does the larger share receive?
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ConclusionWell done! You've mastered Ratio and Proportion. Keep practising to strengthen your skills further!
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