The closed figure formed by an arc of a circle and the radii through its end points is called .........

$\widehat{ACB}$ is a minor arc of $\odot(O, 8 \, cm)$. If $m\angle AOB = 45^\circ$, the length of minor $\widehat{ACB}$ is $\dots \, cm$. (in $\pi$)

In the figure,arcs have been drawn with a radius of $21 \, cm$ each,using vertices $A, B, C,$ and $D$ of quadrilateral $ABCD$ as centers. Find the area of the shaded region in $cm^2$.

The length of the minute hand of a clock is $14 \, cm$. If the minute hand moves from $1$ to $10$ on the dial,then $\ldots \ldots \ldots \ldots \, cm^2$ area will be covered.

Find the area of the shaded region in the figure if $PQ = 24 \, cm$,$PR = 7 \, cm$ and $O$ is the centre of the circle. [Use $\pi = \frac{22}{7}$]

The length of the minute hand of a clock is $7\,cm$. The area of the region swept by it in $20$ minutes is $\ldots \ldots \ldots \,cm^2$.