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 1
The correct answer is Option (1) → (B), (C) and (D) only
Parts form a complete square only if, placed side by side, they fill the square exactly, with no gap and no overlap. (B), (C) and (D) fill a 4 × 4 square when (B) is turned through 90° clockwise and (C) is turned through 90° anticlockwise.
Option (2) — Incorrect. (A) looks like (D) but has one small square more. Together (A), (B) 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. (A) looks like (D) but has one small square more. Together (A), (B) and (C) cover 17 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 (4) — Incorrect. (A) looks like (D) but has one small square more. Together (A), (C) and (D) cover 13 small squares, while the 4 × 4 square has 16, so they cannot make it; they cannot be fitted into any other complete square either.