The length of a rectangular room is $4\, m.$ If it can be partitioned into two equal square rooms,what is the length of the partition in metres?

In the given figure, $ABCDEF$ is a regular hexagon whose side is $6\, cm$. $APF$, $QAB$, $DCR$, and $DES$ are equilateral triangles. What is the area (in $cm^2$) of the shaded region (in $\sqrt{3}$)?

The area of a circle is $220 \text{ cm}^2$. The area of a square inscribed in this circle will be (in $\text{cm}^2$):

If the radius of a circle is reduced by $40 \%$,then its circumference is reduced by (in $\%$).

What will be the area of a semi-$circle$ whose perimeter is $36 \, cm$? (in $cm^2$)

$A$ wire bent in the form of a circle of radius $42 \, cm$ is bent in the form of a rectangle whose sides are in the ratio of $6:5$. The smaller side of the rectangle is (in $cm$)