3D Trigonometry (Edexcel GCSE Maths): Flashcards

Same fundamental rules as 2D

Visualising problem & identifying triangles

Create right triangle → 2D sketch → Use trig

Create a right-angled triangle

Draw a 2D sketch and mark lengths

Use appropriate trig ratio (sin, cos, or tan)

$a^2 + b^2 = c^2$

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

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

$\frac{\text{opposite}}{\text{hypotenuse}}$

$\frac{\text{adjacent}}{\text{hypotenuse}}$

$\frac{\text{opposite}}{\text{adjacent}}$