While calculating the area of a circle,its radius was taken to be $6 \, cm$ instead of $5 \, cm$. The calculated area is $\dots \%$ more than the actual area.

Three circles each of radius $3.5\, cm$ are drawn in such a way that each of them touches the other two. Find the area enclosed between these circles. (in $cm^{2}$)

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 $1,000$)

On a square cardboard sheet of area $784 \, cm^{2}$, four congruent circular plates of maximum size are placed such that each circular plate touches the other two plates and each side of the square sheet is tangent to two circular plates. Find the area of the square sheet not covered by the circular plates (in $cm^{2}$).

The area of the circle that can be inscribed in a square of side $6 \, cm$ is (in $cm^2$) (in $\pi$)

In $\odot(O, 12)$, minor $\widehat{ACB}$ subtends an angle of measure $30^{\circ}$ at the centre. Then, the length of major $\widehat{ADB}$ is $\ldots \ldots \ldots \text{ cm}$. (in $\pi$)