Question

One corner of a long rectangular sheet of paper of width $1$ unit is folded over so as to reach the opposite edge of the sheet. The minimum length of the crease is

• A. $\frac{3\sqrt{3}}{4}$
• B. $\frac{3\sqrt{3}}{2}$
• C. $4\sqrt{3}$
• D. $3\sqrt{3}$

Answer 1

The correct option is A $\frac{3\sqrt{3}}{4}$

From the figure x+y=z

$x=l(1-cos2\theta )$ and $y=xtan\theta$

Also $l^2=x^2+y^2$

we get =$\frac{1}{4si{n}^4\theta co{s}^2\theta }$

So Minimum values of l=$\frac{3\sqrt{3}}{4}$