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0580/31 Oct/Nov 2023, Question 2: Scale Drawings

Cambridge IGCSE Mathematics 0580 · Paper 31 (Core) · Calculator · 10 marks

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The question, in short

Work through circle radius and chord, a scale drawing with ships, regular octagon angles, and an angle in a semicircle.

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

Part (ai) · 1 mark

Given the diameter is 168 mm, state the radius.

  1. 1Radius = 168 ÷ 2 = 84 mm

Answer84

Part (aii) · 1 mark

Draw a chord on the circle shown.

  1. 1Rule a straight line joining any two points on the circumference

AnswerAny chord

Part (bi) · 2 marks

Using 1 cm to 6 km, mark ship C, 45 km from B on a bearing of 124°.

  1. 1On the drawing, 45 km = 45 ÷ 6 = 7.5 cm
  2. 2From the North line at B measure a bearing of 124° clockwise and mark C 7.5 cm from B

AnswerAccurate position marked

Part (bii) · 2 marks

Work out how far ship C actually is from ship A.

  1. 1Measure AC on the drawing: about 9.5 cm
  2. 2Actual distance = 9.5 × 6 = 57 km

Answer57 (accept 55.2 to 57.6)

Part (ci) · 1 mark

Prove that each interior angle of a regular octagon equals 135°.

  1. 1Exterior angle = 360 ÷ 8 = 45°
  2. 2Interior angle = 180 − 360/8 = 135°

Answer180 − 360/8 or ((8 − 2) × 180)/8

Part (cii) · 1 mark

Explain why two regular octagons plus a square fit together at one point with no gaps.

  1. 1Angles at the point: 135 + 135 + 90 = 360
  2. 2They add to 360°, so there are no gaps

Answer135 + 135 + 90 = 360

Part (d) · 2 marks

With DF a diameter and angle EFD = 49°, calculate angle EDF.

  1. 1Angle DEF = 90° (angle in a semicircle)
  2. 2Angle EDF = 180 − 90 − 49 = 41°

Answer41

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Also searched as: 0580/31/O/N/23 · 0580_w23_qp_31 · 0580 w23 31 · question 2.
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