Select the alternative which represents three out of the five alternative…

In a 'three figures fit together to form a square' puzzle, exactly three of the five given pieces must, using rotation only (no flipping), share their touching edges so that every edge length and vertex angle matches its neighbour exactly, leaving no gap and no overlap, and together trace the boundary of one complete square.

Applying this to the given figures:

1. Figure (4) is a plain right-angled triangle; rotated so its right angle sits in a corner of the square, its two legs run along two sides of the square and its hypotenuse becomes one of the internal cut lines.

2. Figure (2) is a quadrilateral with one near-right-angle corner and one sharp point; rotated so its right-angle corner sits in the opposite corner of the square, its sharp point lands inside the square and its slanted edges become the other internal cut lines, one of which matches the cut left by figure (4)'s hypotenuse.

3. The remaining large six-sided figure (3), which has a single notch cut into it, fits into the rest of the square when rotated so its notch edges line up with figure (2)'s sharp point and its long straight edge lines up with figure (4)'s hypotenuse, closing the square with no gap or overlap.

• Figure (1) is a four-sided arrowhead/dart with a concave notch of its own; none of its edge lengths match the cut lines left once figures (2), (3) and (4) are placed, so putting it in place of any of them leaves a gap or forces an overlap.

• Figure (5) is a stepped, mostly rectangular piece with five right angles; its blocky, right-angled profile does not correspond to the single slanted cut needed anywhere in this square, so it cannot close the figure either alongside figures (2)+(3) or alongside figure (4).

Figures (2), (3) and (4) are therefore the three pieces that fit into each other to form the complete square shown.