Author note — to cover (Higher)

Higher only (G10): angles at the circumference standing on the same arc are equal; identify the shared chord, chase angles through multi-theorem figures, and quote the reason. Contrast with cyclic-quadrilateral opposite angles, the sibling result students most often conflate with this one. (G10)

• Fluency — direct questions on angles in the same segment, 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).