A square piece of paper is folded as shown by the dotted line and the arrow, and the folded paper is punched as shown in the last figure. Choose the figure that shows the paper when it is unfolded.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) →
When a folded sheet is opened, every hole is repeated as its mirror image across each fold line, the last fold being opened first. Here the left half is folded over onto the right half, so opening it copies each of the 2 holes across the vertical fold line. So the opened sheet has 4 holes, placed symmetrically about the fold line. A triangle’s copy across a fold line points the other way, as in a mirror.
Option (1) — Incorrect. One of the copies is missing: the opened sheet has 4 holes, this option shows only 3 holes.
Option (2) — Incorrect. The holes are in the right places, but the copies of the triangle are not turned over: across a fold line the copy must point the other way.
Option (3) — Incorrect. It has an extra hole: the opened sheet has 4 holes, this option shows 5 holes.