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4024/11 Oct/Nov 2020, Question 20: Describing Transformations

Cambridge O Level Mathematics 4024 · Paper 11 (Non-calculator) · Non-calculator · 4 marks

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The question, in short

On a grid, triangle A and triangle B are shown; describe the enlargement mapping A to B, then draw and label triangle C after reflecting A in y = −x.

Summarised in our own words. Use the official paper for the exact wording and the diagram.

Part (a) · 2 marks

Complete the description of the enlargement that maps triangle A onto triangle B, giving the missing details.

  1. 1Lines through corresponding vertices, e.g. (1, 2) to (−5, 2) and (3, 3) to (1, 5), meet at (4, 2)
  2. 2Side 2 in A becomes 6 in B: scale factor 6 ÷ 2 = 3
  3. 3Enlargement, centre (4, 2), scale factor 3

AnswerCentre (4, 2), scale factor 3

Part (b) · 2 marks

Draw and label triangle C, the image of triangle A after reflection in the line y = −x.

  1. 1Reflection in y = −x maps (x, y) to (−y, −x)
  2. 2(1, 2) → (−2, −1), (1, 3) → (−3, −1), (3, 3) → (−3, −3)
  3. 3Plot these three points, join them and label the triangle C

AnswerTriangle C with vertices at (−2, −1), (−3, −1), (−3, −3)

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Also searched as: 4024/11/O/N/20 · 4024_w20_qp_11 · 4024 w20 11 · question 20.
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