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0580/13 Oct/Nov 2024, Question 11: Angles in a Triangle

Cambridge IGCSE Mathematics 0580 · Paper 13 (Core) · Calculator · 4 marks

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The question, in short

Use the given angle diagrams to find the unknown angles: w from three lines meeting at a point, and y from an isosceles triangle with a straight line extension.

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

Part (a) · 1 mark

Three lines meet at a point, with a right angle, an 80° angle and angle w. Find w.

  1. 1Angles around a point add to 360°
  2. 2w = 360 − 90 − 80 = 190

Answer190

Part (b) · 3 marks

Triangle BCD is isosceles with DB = DC and angle BDC = 80°. ABC is straight. Find y, angle ABD.

  1. 1Base angles of isosceles triangle BCD: (180 − 80) ÷ 2 = 50°
  2. 2Angle DBC = 50°, and angles on the straight line ABC add to 180°
  3. 3y = 180 − 50 = 130

Answer130

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Also searched as: 0580/13/O/N/24 · 0580_w24_qp_13 · 0580 w24 13 · question 11.
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