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.
- 1Radius = 168 ÷ 2 = 84 mm
Answer84
Part (aii) · 1 mark
Draw a chord on the circle shown.
- 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°.
- 1On the drawing, 45 km = 45 ÷ 6 = 7.5 cm
- 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.
- 1Measure AC on the drawing: about 9.5 cm
- 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°.
- 1Exterior angle = 360 ÷ 8 = 45°
- 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.
- 1Angles at the point: 135 + 135 + 90 = 360
- 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.
- 1Angle DEF = 90° (angle in a semicircle)
- 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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