The Sine Rule

Part of Sine Rule · Section 2 of 5

Key FactsUnit: Geometry & MeasuresGCSE
For sidesa/sin A = b/sin B = c/sin C
For anglessin A/a = sin B/b = sin C/c
Use whenYou have a side and its opposite angle, plus one more
RememberSide a is OPPOSITE angle A, etc.

This key facts covers The Sine Rule within Sine Rule for GCSE Mathematics. Revise Sine Rule in Geometry & Measures for GCSE Mathematics with 12 exam-style questions and 3 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 2 of 5 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

Practice questions for Sine Rule

Which of the following is the sine rule?

  • A. a/sinA = b/sinB = c/sinC
  • B. a² = b² + c² − 2bc cosA
  • C. Area = ½ab sinC
  • D. sinA/a = sinB/b + sinC/c
1 markfoundation

Explain what is meant by the ambiguous case of the sine rule, and state when it can occur.

3 markshigher

Quick recall flashcards

Sine Rule
a/sin A = b/sin B = c/sin C
Sine Rule
a/sinA = b/sinB = c/sinC. Use when you have a matched pair (side with opposite angle).

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