In a circle with radius $14 \, cm$,the area of the minor sector corresponding to minor $\widehat{ACB}$ is $77 \, cm^2$. Then,minor $\widehat{ACB}$ subtends an angle of measure $\dots$ at the centre. (in $^\circ$)

As shown in the diagram,$\overline{AC}$ is a diameter of the circle with centre $O$. $\Delta ABC$ is inscribed in the circle. If $AC = 35 \, cm$,$AB = 21 \, cm$ and $BC = 28 \, cm$,find the area of the shaded region in $cm^2$.

Is the area of the circle inscribed in a square of side $a \, cm$ equal to $\pi a^2 \, cm^2$? Give reasons for your answer.

The radius of a circular ground is $35 \, m$. Outside it,a road of width $3.5 \, m$ runs around it. Find the area of the road in $m^2$.

Four circular cardboard pieces of radii $7 \, cm$ are placed on a paper in such a way that each piece touches the other two pieces. Find the area of the portion enclosed between these pieces (in $cm^2$).

The side length of square $ABCD$ is $14 \, cm$. As shown in the diagram,circles with radius $7 \, cm$ are drawn with each vertex as the centre so that each circle touches two other circles externally. Find the area of the shaded region in $cm^2$.