Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 3 - No. 6)

Which tools/concepts are necessary for applying the trigonometry ratios?

A well-labeled diagram.

Knowing the angle measurement.

Understanding inverse operations.

Knowledge of each trigonometric ratio formula (SOH CAH TOA)

A well labeled diagram, inverse operations and SOH CAH TOA are all important in understanding trigonometry.