Keystones — Capstone
Five GCSE retrieval questions · 8 June 2026 · mathsvault.uk/keystones
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1. Number Rationalising the denominator
Rationalise the denominator: 6/√12
Answer: √3 (or 3√3⁄3) -
2. Algebra Factorising non-monic quadratics
Factorise: 8x² + 10x - 12
Answer: (4x - 3)(2x + 4) -
3. Geometry SOHCAHTOA — missing length
Adjacent = 19cm, angle = 53°. Find opposite
Answer: 25.2cm -
4. Ratio Reverse percentages
A price of £325.35 includes a 35% increase. What was the price before the increase?
Answer: £241.00 -
5. Statistics Mean
The mean of 4 numbers is 21. If 3 of them are 28, 21, 30, what is the missing number?
Answer: 5