The area of $\odot(O, r)$ is $240 \, cm^2$. In $\odot(O, r)$,minor arc $\widehat{ACB}$ subtends an angle of measure $45^\circ$ at the centre. Then,the area of minor sector $OACB$ is $\dots \dots \dots \, cm^2$.

The radius of a circular ground is $63 \, m$. Find the cost of fencing its boundary at the rate of ₹ $50 / m$. Find the cost of levelling the ground at the rate of ₹ $40 / m^2$.

Will it be true to say that the perimeter of a square circumscribing a circle of radius $a \, cm$ is $8 a \, cm$? Give reasons for your answer.

As shown in the diagram,the side length of square garden $ABCD$ is $60\, m$. Flower beds are prepared in the shape of circular segments on two opposite sides of the square. The centre of the circles for these segments is the point of intersection $O$ of the diagonals of square $ABCD$. Find the total area of the two flower beds. (Use $\pi=3.14$) (in $m^2$)

The length of a minor arc in a circle with radius $28 \ cm$ is $22 \ cm$. Find the measure of the angle subtended at the centre by this arc. Also,find the area of the sector formed by this arc.

$\widehat{ACB}$ 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 $\pi$)