Objective
Connect circle and coordinate geometry at the appropriate tier.
Calculator: Non-calculator core; calculator optional only for checking where labelled.

Recall
Retrieve the key fact or method needed for circle equations pathway.
Core practice
A circle has equation x²+y²=49. Find y-values when x=0 and when x=5.
Reasoning
Can (7,7) lie on the circle x²+y²=49? Justify by substitution.
Exam-style
Use a labelled diagram to calculate the missing value. State the theorem or formula and include units where needed.