The Sine and Cosine Rules (AQA GCSE Maths): Flashcards

Any triangle (not just right-angled)

Lowercase: a, b, c

Uppercase: A, B, C

Side a

$\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}$

$a^2 = b^2 + c^2 - 2bc \cos A$

$\cos A = \frac{b^2 + c^2 - a^2}{2bc}$

Area = $\frac{1}{2}ab \sin C$

2 angles & any side OR 2 sides & angle not between

2 sides & enclosed angle OR all 3 sides