4.8.5

Sine Rule

Test yourself

Sine and Cosine Rules

We can use the sine and cosine rules to calculate angles and lengths in triangles.

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Labelling triangles

  • Use lowercase letters for the sides and capital letters for the angles opposite each side.
Illustrative background for Swapping A, B and CIllustrative background for Swapping A, B and C ?? "content

Swapping A, B and C

  • Note that the cosine rule can be written for the other angles too:
    • c2 = a2 + b2 - 2ab cos C
    • b2 = a2 + c2 - 2ac cos B

Jump to other topics

1Number

1.1Using Numbers

1.2Fractions, Decimals & Percentages

1.3Powers & Roots

1.4Accuracy

2Algebra

2.1Introduction to Algebra

2.2Manipulating Algebra

2.3Proofs & Functions

2.4Straight Line Graphs

2.5Common Graphs

2.6Transformations & Tangents

2.7Properties of Graphs

2.8Solving Equations

2.9Inequalities

2.10Sequences

3Ratio

4Geometry

4.1Introduction to Geometry

4.2Triangles & Quadrilaterals

4.3Transformations

4.4Circle Basics

4.5Circle Theorems

4.6Measurements & Units

4.7Calculating Area

4.8Triangle Formulae

4.93D Shapes

4.10Vectors

5Probability

6Statistics

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