The circumference of the wheels of a truck is $440\, cm .$ They make $250$ rotations per minute. Then, the speed of the truck is $\ldots \ldots \ldots \ldots km / h$.
$50$
$60$
$66$
$88$
In $\odot( O , 4\, cm ),$ the length of chord $\overline{ AB }$ is $4 \,cm .$ Then, $m \angle AOB =\ldots \ldots \ldots \ldots$
The length of the minute hand of a clock is $12\,cm .$ The area of the region swept by it in $5$ minutes is $\ldots \ldots \ldots . . cm ^{2} .(\pi=3.14)$
In a circle with radius $21 \,cm$, the length of a minor arc is $33 \,cm .$ Find the measure of the angle subtended at the centre by this arc. Also find the area of the minor sector and the minor segment formed by it.
An archery target has three regions formed by three concentric circles as shown in $Fig.$ If the diameters of the concentric circles are in the ratio $1: 2: 3,$ then find the ratio of the areas of three regions.
Areas of two circles are equal. Is it necessary that their circumferences are equal? Why?