Which of the following sets of parts can be fitted together, without gaps or overlaps, to make a complete square? The parts may be turned round.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A), (B) and (C) only
Parts form a complete square only if, placed side by side, they fill the square exactly, with no gap and no overlap. (A), (B) and (C) fill a 4 × 4 square when (B) is turned through 90° clockwise and (C) is turned through 180°.
Option (1) — Incorrect. (D) looks like (B) but has one small square less. Together (A), (C) and (D) cover 15 small squares, while the 4 × 4 square has 16, so they cannot make it; they cannot be fitted into any other complete square either.
Option (2) — Incorrect. (D) looks like (B) but has one small square less. Together (B), (C) and (D) cover 11 small squares, while the 4 × 4 square has 16, so they cannot make it; they cannot be fitted into any other complete square either.
Option (3) — Incorrect. (D) looks like (B) but has one small square less. Together (A), (B) and (D) cover 12 small squares, while the 4 × 4 square has 16, so they cannot make it; they cannot be fitted into any other complete square either.