IGCSE Maths / Further trigonometry

Choosing between the sine rule and the cosine rule revision notes

Edexcel International GCSE Maths (4MA1), chapter 25: Further trigonometry, specification point 4.8c. Part of the full course.

Watch the video lesson · IGCSE Maths past papers

Choose a triangle rule from the information you are given, before you start calculating. Check for a right angle first, then look for a known side and its opposite angle.

More lessons in Further trigonometry

• The sine rule: finding a missing side
• The sine rule: finding a missing angle
• The ambiguous case of the sine rule
• The cosine rule: finding a missing side
• The cosine rule: finding a missing angle
• Area of a triangle using half ab sin C
• Finding a side or an angle from a given area
• Area of a segment
• The angle between a line and a plane
• Trigonometry in pyramids and cones
• Problem solving in three dimensions