IGCSE Practice

Edexcel IGCSE·Mathematics 4MA1 Right Angled Triangles
📋Key knowledge — Trigonometry

Formulas & equations

  • sin θ = opposite ÷ hypotenuse (SOHCAHTOA)
  • cos θ = adjacent ÷ hypotenuse
  • tan θ = opposite ÷ adjacent
  • Sine rule: a/sin A = b/sin B = c/sin C
  • Cosine rule: a² = b² + c² − 2bc cos A
  • Area of triangle = ½ ab sin C
  • Exact values: sin 30°=½, cos 30°=√3/2, tan 30°=1/√3
  • Exact values: sin 45°=√2/2, cos 45°=√2/2, tan 45°=1
  • Exact values: sin 60°=√3/2, cos 60°=½, tan 60°=√3

Key facts & rules

  • SOHCAHTOA only works in right-angled triangles.
  • Sine rule: use when you know 2 sides + opposite angle, or 2 angles + any side.
  • Cosine rule: use when you know 3 sides (to find an angle), or 2 sides + included angle.
  • Bearing: measured clockwise from North, always written as 3 digits (e.g. 045°).
  • Angle of elevation: measured upward from horizontal. Angle of depression: measured downward from horizontal.
  • For graphs: sin and cos have period 360°, amplitude 1. tan has period 180°.

Right angled triangles

13 Edexcel IGCSE 4MA1 past paper questions on right angled triangles — Foundation and Higher, with mark schemes.

Question 1 of 13

November 2023 · Paper 1F · Q24 Foundation
Right angled triangles question 1
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Question 2 of 13

June 2023 · Paper 2F · Q28 Foundation
Right angled triangles question 2
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Question 3 of 13

June 2024 · Paper 2F · Q21 Foundation
Right angled triangles question 3
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Question 4 of 13

June 2023 · Paper 2FR · Q24 Foundation
Right angled triangles question 4
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Question 5 of 13

June 2024 · Paper 2FR · Q26 Foundation
Right angled triangles question 5
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Question 6 of 13

November 2023 · Paper 1H · Q10 Higher
Right angled triangles question 1
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Question 7 of 13

January 2023 · Paper 1HR · Q9 Higher
Right angled triangles question 2
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Question 8 of 13

June 2023 · Paper 2H · Q12 Higher
Right angled triangles question 3
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Question 9 of 13

June 2023 · Paper 2H · Q22 Higher
Right angled triangles question 4
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Question 10 of 13

November 2023 · Paper 2H · Q2 Higher
Right angled triangles question 5
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Question 11 of 13

June 2024 · Paper 2H · Q5 Higher
Right angled triangles question 6
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Question 12 of 13

November 2024 · Paper 2H · Q3 Higher
Right angled triangles question 7
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Question 13 of 13

June 2023 · Paper 2HR · Q9 Higher
Right angled triangles question 8
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