4024/12 May/Jun 2021, Question 2: Lines of Symmetry
Cambridge O Level Mathematics 4024 · Paper 12 (Non-calculator) · Non-calculator · 2 marks
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The question, in short
For each of the two shaded shapes shown, complete the statements by giving the number of lines of symmetry and the order of rotational symmetry.
Summarised in our own words. Use the official paper for the exact wording and the diagram.
Solution · 2 marks
- 1Hexagon: a line through the midpoints of opposite sides cuts one black triangle and the opposite white triangle in half and swaps the others colour-for-colour, so it is a mirror line; there are 3 such lines
- 2(Lines through opposite vertices swap black and white triangles, so they are not mirror lines.) 3 lines of symmetry
- 3Turning it by 120° takes each black triangle onto a black one, so rotational symmetry of order 3
- 4Square: no mirror line keeps the shading, so 0 lines of symmetry
- 5Turning it by 180° about the centre gives the same pattern (but 90° does not), so rotational symmetry of order 2
AnswerLeft shape (hexagon): 3 lines of symmetry, rotational symmetry of order 3 Right shape (square): 0 lines of symmetry, rotational symmetry of order 2
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Also searched as: 4024/12/M/J/21 · 4024_s21_qp_12 · 4024 s21 12 · question 2.
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