Author note — to cover

The distance between coordinate points as the hypotenuse of the right-angled triangle the grid supplies, coordinate differences as the two legs, surd or rounded answers, no memorised distance formula required. Links G11's coordinate problems with G20. Midpoints stay on Properties' coordinate page. Both tiers. (G20, G11)

• Fluency — direct questions on the distance between two points, 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).