Covers Lessons 15–20: Triangles, quadrilaterals, polygons, nets and symmetry.
Question 9 3 marks
(a) A triangle has angles 40° and 70°. Classify it by angles. 1 mark
(b) Name a quadrilateral with four equal sides but not necessarily right angles. 1 mark
(c) How many lines of symmetry does a regular hexagon have? 1 mark
(a) Third angle = 70°, so it is acute (all angles < 90°) [1]
(b) Rhombus [1]
(c) 6 [1]
Question 10 3 marks
(a) Find the angle sum of a hexagon. 1 mark
(b) Find each interior angle of a regular pentagon. 2 marks
(a) (6 - 2) × 180 = 720° [1]
(b) (5 - 2) × 180 = 540°; 540 ÷ 5 = 108° [2]
Question 11 4 marks
(a) Describe the difference between a prism and a pyramid. 2 marks
(b) A cube has side length 4 cm. Find its volume and surface area. 2 marks
(a) A prism has two identical bases and rectangular faces [1]. A pyramid has one base and triangular faces meeting at an apex [1].
(b) V = 4³ = 64 cm³ [1]; SA = 6 × 16 = 96 cm² [1]