Explanation

In right triangles: sin θ = opposite/hypotenuse, cos θ = adjacent/hypotenuse, tan θ = opposite/adjacent. Remember: SOH-CAH-TOA.

Special angles: sin 30° = 1/2, cos 30° = √3/2, tan 30° = 1/√3. sin 45° = cos 45° = 1/√2, tan 45° = 1. sin 60° = √3/2, cos 60° = 1/2.

Inverse functions find angles: if sin θ = 0.5, then θ = sin⁻¹(0.5) = 30°. Use calculator for non-special angles. Remember: sin²θ + cos²θ = 1.