0580/31 May/Jun 2026, Question 28: The Cosine Ratio
Cambridge IGCSE Mathematics 0580 · Paper 31 (Core) · Calculator · 2 marks
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The question, in short
Using a right-angled triangle with hypotenuse 9 cm and base 6 cm, calculate the angle x at the left vertex.
Summarised in our own words. Use the official paper for the exact wording and the diagram.
Solution · 2 marks
- 1cos x = adjacent/hypotenuse = 6/9
- 2x = cos⁻¹(6/9)
- 3x = 48.2
Answer48.2 or 48.18 to 48.19
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