Trigonometry · SS2

Sine & cosine rules

The sine and cosine rules for triangles that are not right-angled.

Learn

  1. 1The sine rule and the cosine ruleTwo rules for triangles without a right angle: which one to use, how to set it out, and the sign of cos for obtuse angles.Done20 min
  2. 2Bearings with any triangleThe hardest bearing questions: find the angle inside the triangle from the bearings, then use the cosine rule for the distance and the sine rule for the new bearing.Done15 min

Practise

Answer sine & cosine rules questions one at a time. You'll know straight away whether you're right, with hints and the working step by step.

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Past questions (40)

From 1983–2023: 18 WAEC, 1 NECO, 21 JAMB. Theory questions first, then objective, newest first.

Theory (18)

Objective (22)