Author note — to cover

Count mirror lines of triangles, quadrilaterals, regular polygons and letter-style shapes, and complete a figure on a grid so a given line, including a diagonal, becomes a mirror. Symmetry as a defining shape property per G1. Reflection as a transformation producing an image is its own page. Both tiers. (G1)

• Fluency — direct questions on line symmetry, 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).