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4MA1/1FR Jan 2022, Question 8: Multi-Step Angle Reasoning

Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 1FR (Foundation) · Calculator · 5 marks

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The question, in short

Use the straight line ABC and triangle BCD with angles 93° and 42° to find x, then use four straight lines through O with angles 100°, a right angle, 114° and y to find y and justify it.

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

Part (a) · 2 marks

Find x, the exterior angle at B on the straight line ABC, using the triangle BCD angles 93° and 42°.

  1. 1Exterior angle of a triangle = sum of the two opposite interior angles.
  2. 2x = 93 + 42 = 135

Answer135

Part (bi) · 2 marks

Find y, the angle TOP, using the angles 100°, 90° and 114° around point O.

  1. 1Angles at a point add up to 360°.
  2. 2The right angle is 90°: 90 + 100 + 114 = 304
  3. 3y = 360 − 304 = 56

Answer56

Part (bii) · 1 mark

State the geometric reason that justifies the value found for y.

  1. 1Angles at a point sum to 360°

AnswerAngles at a point sum to 360°

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