Author note — to cover

A equals pi r squared, a formula G17 says must be known, squaring only the radius and halving any given diameter before substituting; reverse from area to radius with a square root. Contrast with circumference so the two formulas are not swapped. Both tiers. (G17)

• Fluency — direct questions on area 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).