ECZ 2025 · O-Level Paper 1 — Similarity and Congruency

Two similar solids X and Y have surface areas 5 cm2 and 20 cm2 respectively. If the volume of solid Y is 200 cm3, calculate the volume of solid X.

  • A. 50 cm3
  • B. 25 cm3
  • C. 100 cm3
  • D. 12.5 cm3

Verified working — step 1

Similar solids link three ratios: lengths k, areas k2, volumes k3. Given the AREA ratio, step down to lengths first, then up to volumes.

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Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.

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