The circumference of the wheels of a truck is $440 \, cm$. They make $250$ rotations per minute. Then,the speed of the truck is $\ldots \ldots \ldots \ldots \, km/h$.

If $\theta$ is the angle (in degrees) of a sector of a circle of radius $r$,then the area of the sector is:

The maximum area of a triangle inscribed in a semicircle with diameter $50 \, cm$ is ........... $cm^{2}$.

As shown in the adjoining diagram,the length of the side of the square plot $ABCD$ is $50 \, m$. At each vertex of the plot,a flower bed in the shape of a sector with radius $10 \, m$ is prepared. Find the area of the plot excluding the flower beds. $(\pi = 3.14)$ (in $m^2$)

The diagram below is formed by three semicircles. If $OA = OB = 70\, cm,$ find the area of the figure formed (in $cm^2$).

The radius of a circle whose circumference is equal to the sum of the circumferences of the two circles of diameters $36 \, cm$ and $20 \, cm$ is (in $cm$)