Author note — to cover (Higher)

Higher page, per the A16 braces. Recognise and use x² + y² = r² for a circle centred at the origin: state the radius from the equation and vice versa, test whether points lie on, inside or outside, and sketch. Circles centred elsewhere, (x − a)² + (y − b)² = r², are A level. (A16)

• Fluency — direct questions on the equation of a circle, 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).