Author note — to cover

G21's exact values, both tiers: sin and cos at 0, 30, 45, 60 and 90 degrees, and tan at 0, 30, 45 and 60 only — tan 90 is undefined and outside G21. Derive from the half-equilateral and right-isosceles triangles for non-calculator questions. Surd arithmetic support is Number's N8. (G21)

• Fluency — direct questions on exact trigonometric values, limited to this lesson's stated scope (4 questions).
• Application — use the same skill in unfamiliar or contextual questions without introducing a later method (4 questions).
• Check — questions built around the exclusions and likely misconceptions named in the lesson brief (4 questions).