Henry Ernest Dudeney/Puzzles and Curious Problems/201 - Square and Triangle/Solution

by : $201$

 * Square and Triangle

Solution
Fold the square in half to get the crease $EF$.


 * Dudeney-Puzzles-and-Curious-Problems-201-solution.png

Fold along $AH$ to get $B$ to lie on $EF$ at $G$.

With that fold in place, fold $HGJ$.

While $B$ is on $G$, fold $AB$ back on $AH$ to get the line $AK$.

You can now fold the triangle $AJK$, which is the largest possible equilateral triangle that can be obtained.