Keystones — Capstone
Five GCSE retrieval questions · 20 February 2026 · mathsvault.uk/keystones
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1. Number Simplifying surds
Simplify: √243
Answer: 9√3 -
2. Algebra Completing the square
Complete the square: x² + 4.6x
Answer: (x + 2.3)² - 5.29 -
3. Geometry Area using ½ab sin C
Find area of triangle: a = 12cm, b = 19cm, angle = 50°
Answer: 87.3cm² -
4. Ratio Combining two ratios
a:b is 3:2 and b:c is 1:3. Find a:b:c.
Answer: 3:2:6 -
5. Statistics Averages and range
Find the mean, median and range of: 49, 11, 55, 61, 68, 77, 87, 55
Answer: Mean = 57.9, Median = 61, Range = 76