The cost of erecting a wall all around a circular ground at the rate of $₹ 60/m$ is $₹ 26,400$. Find the cost of levelling the ground at the rate of $₹ 50/m^2$. (in $₹$) (in $1,000$)

In $Fig.$,$ABCD$ is a square of side $14 \, cm$. With centres $A, B, C$ and $D$,four circles are drawn such that each circle touches externally two of the remaining three circles. Find the area of the shaded region (in $cm^2$). $\left[\text{Use } \pi = \frac{22}{7}\right]$

In a circle with radius $7 \, cm$,the area of a minor sector can be $\ldots \ldots \ldots \ldots \, cm^{2}$.

In $\odot(O, 6)$, $\widehat{ABC}$ is a major arc and $m \angle AOC = 60^{\circ}$. Then, the length of major $\widehat{ABC}$ is ........... (in $\pi$)

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 area of the minor segment formed by it.

The ratio of the radii of two circles is $4: 5$. Then,the ratio of their areas is...........