As shown in the diagram,the side length of square $ABCD$ is $21 \ cm$. $\widehat{APC}$ is an arc of $\odot(B, BA)$ and $\widehat{AQC}$ is an arc of $\odot(D, DA)$. Find the area of the shaded portion. (in $cm^2$)

In $\odot (P, 20)$,the area of a minor sector is $150\, cm^2$. The length of the arc corresponding to that sector is $\dots\, cm$.

The diameter of a circle with area $154\,cm^{2}$ is $\ldots \ldots \ldots . cm$.

In $\odot(O, r)$,chord $\overline{AB}$ subtends a right angle at the centre. The area of the minor segment $\overline{AB} \cup \widehat{ACB}$ is $114 \, cm^2$ and the area of $\Delta OAB$ is $200 \, cm^2$. Then,the area of the minor sector $OACB$ is ......... $cm^2$.

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 $cm^{2}$)

Find the area of the segment of a circle of radius $12 \, cm$ whose corresponding sector has a central angle of $60^{\circ}$ (Use $\pi = 3.14$).