Author note — to cover

Base times perpendicular height, with diagrams deliberately labelling the slant side as a distractor; explain by shearing or cutting to a rectangle why the slant answer is always too big. G16 lists the formula among those to know. The rhombus uses the same formula. Both tiers. (G16)

• Fluency — direct questions on area of a parallelogram, 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).