Some of the parts shown below make a complete square when they are fitted together. Which set of parts does this? (Parts may be turned round.)
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (B), (C), (D) and (E) 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), (D) and (E) fill a 5 × 5 square when (B) is turned through 180° and (E) is turned through 180°.
Option (2) — Incorrect. (A) has as many small squares as (E) but one of them is in a different place. Together (A), (C), (D) and (E) cover 23½ small squares, while the 5 × 5 square has 25, so they cannot make it; they cannot be fitted into any other complete square either.
Option (3) — Incorrect. (A) has as many small squares as (E) but one of them is in a different place. Together (A), (B), (C) and (E) cover 24½ small squares, while the 5 × 5 square has 25, so they cannot make it; they cannot be fitted into any other complete square either.
Option (4) — Incorrect. (A) has as many small squares as (E) but one of them is in a different place. (A), (B), (C) and (D) cover as many small squares as the 5 × 5 square, but they cannot be fitted into it, or into any complete square, without a gap or an overlap.