4MA1/2F Nov 2021, Question 20: Similar Triangles
Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 2F (Foundation) · Calculator · 4 marks
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The question, in short
Similar triangles ABC and DEF with AC = 45 cm, DF = 20 cm, DE = 36 cm; find side lengths using corresponding sides.
Summarised in our own words. Use the official paper for the exact wording and the diagram.
Part (a) · 2 marks
Work out the length of AB using the similar triangles and given side lengths.
- 1AC matches DF: scale factor = 45 ÷ 20 = 2.25
- 2AB matches DE: AB = 36 × 2.25 = 81
Answer81
Part (b) · 2 marks
Given BC = 54 cm, work out the length of EF.
- 1BC matches EF, and DEF is the smaller triangle.
- 2EF = 54 ÷ 2.25 = 24
Answer24
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