SOHCAHTOA (GCSE)
Right-angled trig: pick the ratio that uses your two known quantities.
GCSE expects fluent application: identify the angle, label the sides (opp/adj/hyp), pick sin/cos/tan, solve for the unknown.
Worked examples
Hyp 10, θ = 30°: opp = 10 sin 30 = 5; adj = 10 cos 30 ≈ 8.66.
Opp 7, adj 24: tanθ = 7/24 ⇒ θ = arctan(7/24) ≈ 16.3°.
Always check the angle is in degrees on the calculator.
Frequently asked questions
Inverse trig button?
sin−1, cos−1, tan−1 on a Casio. Use to find an angle from a ratio.
Angle of elevation/depression?
Standard exam context: angle from horizontal up (elevation) or down (depression). Same SOHCAHTOA logic.