The diameter of a circular wheel is $7\, m$. How many revolutions will it make in travelling $22\, km$?

$A$ steel sphere of radius $4 \, cm$ is drawn into a wire of diameter $4 \, mm$. Find the length of the wire in $mm$.

$A$ solid metallic sphere of radius $21\, cm$ is melted and recast into a cone with diameter of the base as $21\, cm$. What is the height (in $cm$) of the cone?

In the given figure,$PB$ is one-third of $AB$ and $BQ$ is one-third of $BC.$ If the area of $BPDQ$ is $20 \, cm^{2},$ then what is the area (in $cm^{2}$) of $ABCD$?

In the given figure,$ABCD$ is a square of side $14 \ cm$. $E$ and $F$ are mid-points of sides $AB$ and $DC$ respectively. $EPF$ is a semicircle whose diameter is $EF$. $LMNO$ is a square. What is the area (in $cm^2$) of the shaded region?

In the given figure,if $O$ is the centre of the circle,then find the value of $y$?