Find the length of a rope by which a cow must be tethered in order that it may be able to graze an area of $9856 \, m^{2}$. (in $m$)

The radius of a coin is $1\, cm$. If four of these coins are placed on a table so that the rim of each touches that of the other two,find the area of the unoccupied space between them. (in $cm^2$)

$A$ square is inscribed in a circle whose radius is $4\, cm$. The area of the portion between the circle and the square is

$A$ circular road runs round a circular ground. If the difference between the circumferences of the outer circle and the inner circle is $66 \, m$,the width of the road is ....... $m$.

Four equal-sized circular plates of maximum diameter are cut off from a square paper sheet of area $784 \, cm^2$. The circumference of each plate is ...... $m$.

The area of the incircle of an equilateral triangle of side $42 \ cm$ is (in $cm^2$)