The perimeter of a sector of a circle with central angle $90°$ is $25 \mathrm{cm}.$ If the area of the minor segment of the circle is $k {\mathrm{cm}}^2$, then find the value of $k$. [Use $\mathrm{\pi }=\frac{22}{7}$]

If the area of shaded portions of the following figure is $k {\mathrm{cm}}^2$ then find $k$ correct up to four decimal places.

If the area of shaded portions of the following figure is $k {\mathrm{cm}}^2$ then find $k$ correct up to one decimal place.