The length of a minor arc of $\odot(O, 7)$ can be $\ldots \ldots \ldots \ldots$ units.

The ratio of the areas of two circles is $25: 36$. Then,the ratio of their circumferences is:

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 $\pi = \frac{22}{7}$]

In a circle with radius $20 \,cm$,the measures of the angle subtended at the centre for two distinct sectors are $15^{\circ}$ and $90^{\circ}$. Then,the ratio of the areas of those sectors is $\ldots \ldots \ldots$.

In a circle,the area of a sector formed by two radii perpendicular to each other is $38.5 \, cm^2$. Find the radius of the circle (in $cm$).

The radius of a circular ground is $90\, m$. Inside it,a road of width $10\, m$ runs around its boundary. Find the area of the road. $(\pi=3.14)$ (in $m^2$)