Keystones — Capstone
Five GCSE retrieval questions · 29 December 2025 · mathsvault.uk/keystones
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1. Number Simplifying surds
Simplify: √125
Answer: 5√5 -
2. Algebra Completing the square
Complete the square: x² + 3.2x
Answer: (x + 1.6)² - 2.56 -
3. Geometry Area using ½ab sin C
Find area of triangle: a = 17cm, b = 21cm, angle = 74°
Answer: 171.6cm² -
4. Ratio Combining two ratios
a:b is 3:2 and b:c is 1:2. Find a:b:c.
Answer: 3:2:4 -
5. Statistics Averages and range
Find the mean, median and range of: 91, 49, 51, 15, 16, 39, 18
Answer: Mean = 39.9, Median = 39, Range = 76