A square piece of paper is folded as shown by the dotted lines and the arrows, 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 3
The correct answer is Option (3) →
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 first the right half is folded over onto the left half and then the bottom half is folded up onto the top half. Opening the second fold copies the hole across the horizontal fold line; opening the first fold then copies all of them across the vertical fold line. So the opened sheet has 4 holes, placed symmetrically about the fold lines. A triangle’s copy across a fold line points the other way, as in a mirror.
Option (1) — Incorrect. Only the second fold has been opened: the copies across the vertical fold line are missing, so it shows only 2 holes.
Option (2) — Incorrect. It has an extra hole: the opened sheet has 4 holes, this option shows 5 holes.
Option (4) — 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.