On a square cardboard sheet of area $784 \,cm ^{2}$, four congruent circular plates of maximum size are placed such that each circular plate touches the other two plates and each side of the square sheet is tangent to two circular plates. Find the area of the square sheet not covered by the circular plates. (in $cm ^{2}$)
$168$
$174$
$172$
$616$
In $Fig.$ a circle of radius $7.5 \,cm$ is inscribed in a square. Find the area of the shaded region (Use $\pi=3.14$ ) (in $cm^2$)
In a circle with radius $8.4\, cm ,$ a minor arc subtends an angle of measure $60$ at the centre. Find the area of the minor sector and the major sector corresponding to this arc.
In the adjoining diagram, $\overline{ AB }$ and $\overline{ CD }$ are diameters of $\odot( O , 7\, cm )$ perpendicular to each other. A circle is drawn with diameter $\overline{ OD }$. Find the area of the shaded region. (in $cm^2$)
From a circular metallic sheet with radius $21\, cm ,$ a regular hexagon of side $21\, cm$ is cut off. Find the area of the remaining sheet. $(\sqrt{3}=1.73)$ (in $cm^2$)
The length of the minute hand of a clock is $5\, cm$. Find the area swept by the minute hand during the time period $6: 05$ $a.m.$ and $6: 40$ $a.m.$ (in $cm^2$)