Author note — to cover

Exterior angles of any polygon sum to 360 degrees: justify it as one full turn, find a missing exterior angle, use interior plus exterior equals 180 on a straight line, and recover a regular polygon's number of sides from one exterior angle. Both tiers. (G3)

• Fluency — direct questions on exterior angles of a polygon, 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).