Primary 4 Mathematics Geometry Quiz

Primary 4 Mathematics Quiz - Geometry (Answer Key)

Total Marks: 40
Topic: Geometry (Angles, Symmetry, Nets, Properties)

Section A Answers

1. C (120°) [1 mark]
Teaching: Obtuse angles are greater than 90° but less than 180°. 35° is acute, 90° right, 180° straight. Only 120° fits.

2. D (4) [1 mark]
Teaching: A square has 4 equal sides and 4 right angles. Lines of symmetry: 2 diagonals + 2 midlines = 4.

3. A (Shape A) [1 mark]
Teaching: A cube net must have 6 squares that fold without overlap. The cross (Shape A) is a valid net. B (5 squares) cannot close; C and D have too few.

4. A (Acute) [1 mark]
Teaching: Acute < 90°. 45° is less than 90°, so acute.

5. C (2) [1 mark]
Teaching: Opposite sides of a rectangle are parallel. Two pairs: top-bottom and left-right.

Section B Answers

6. ∠ABC = 65° [1 mark]
Teaching: Place protractor centre at B, align baseline with BA, read where BC crosses: 65°.

7. Draw 110° at P [2 marks]

• Mark baseline ray from P (1 mark)
• Draw second ray at 110° from baseline using protractor (1 mark)
  Teaching: 110° is obtuse. From horizontal right ray, count up 110°.

8. Common factors of 24 and 36: 1, 2, 3, 4, 6, 12 [2 marks]
Working:
Factors of 24: 1,2,3,4,6,8,12,24
Factors of 36: 1,2,3,4,6,9,12,18,36
Common: 1,2,3,4,6,12
(1 mark list 24 & 36 factors, 1 mark common correct)

9. Shape with 1 line of symmetry [2 marks]

• Shape drawn (1 mark)
• Line of symmetry correct (1 mark)
  Example: Isosceles triangle with vertical line. Teaching: Fold along line, both sides match.

10. Right angle [1 mark]
Teaching: Square corner mark = 90° = right angle.

11. Cube [1 mark]
Teaching: Net of 6 squares folding to closed box = cube.

12. 48,000 [1 mark]
Working: 47,825 → thousands digit 7, next digit 8 ≥5 → round up 47,000→48,000.

13. 110° [2 marks]
Working: Straight angle = 180°. 180° − 70° = 110° (2 marks for method + answer)
Teaching: Straight line angle is always 180°.

14. 3 [1 mark]
Teaching: Equilateral triangle has 3 equal sides; each altitude/midline is symmetry: 3 lines.

15. 270° [1 mark]
Working: 3 × 90° = 270°.

Section C Answers

16. ∠PQS = 75° [2 marks]
Working: ∠PQS = ∠PQR + ∠RQS = 40° + 35° = 75° (1 mark method, 1 mark answer)
Teaching: Adjacent angles at same vertex add.

17. 4 lines of symmetry [2 marks]

• Drawing shows 4 lines (2 diag, 2 mid) (1 mark)
• Answer 4 (1 mark)
  Teaching: Square always 4 lines.

18. Opposite shaded = face B (or labelled opposite) [2 marks]
Working: In cross net, centre opposite is the one not adjacent when folded. (1 mark reasoning, 1 mark answer)
Teaching: Fold net mentally; centre meets far end.

19. Sum = 110° [2 marks]
Working: Measure ∠D ≈50°, ∠E ≈60°; sum = 110° (1 mark measures, 1 mark sum)
Teaching: Triangle angle sum is 180°, so third ≈70°.

20. 2 lines of symmetry [2 marks]

• Rectangle drawn 4×2 cm (1 mark)
• Answer 2 (mid horizontal, mid vertical) (1 mark)
  Teaching: Rectangle (non-square) has 2 symmetry lines.