0580/21 Oct/Nov 2025, Question 2: Angles in a Triangle
Cambridge IGCSE Mathematics 0580 · Paper 21 (Extended) · Non-calculator · 3 marks
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The question, in short
Triangle ABC has AC = BC; an exterior line at C makes 82° with CA and 148° with CB. Work out angle CAB.
Summarised in our own words. Use the official paper for the exact wording and the diagram.
Solution · 3 marks
- 1Angles at a point: angle ACB = 360 − 148 − 82 = 130°
- 2Triangle is isosceles (AC = BC), so angle CAB = (180 − 130) ÷ 2
- 3= 25°
Answer25
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Also searched as: 0580/21/O/N/25 · 0580_w25_qp_21 · 0580 w25 21 · question 2.
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