Keystones — Capstone
Five GCSE retrieval questions · 22 December 2025 · mathsvault.uk/keystones
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1. Number Simplifying surds
Simplify: √108
Answer: 6√3 -
2. Algebra Completing the square
Complete the square: x² + 2.8x
Answer: (x + 1.4)² - 1.96 -
3. Geometry Area using ½ab sin C
Find area of triangle: a = 20cm, b = 27cm, angle = 77°
Answer: 263.cm² -
4. Ratio Combining two ratios
a:b is 2:1 and b:c is 2:5. Find a:b:c.
Answer: 4:2:5 -
5. Statistics Averages and range
Find the mean, median and range of: 72, 82, 75, 92, 95, 53, 17, 65, 86
Answer: Mean = 70.8, Median = 75, Range = 78