The circumference of a circular ground is $352\, m$. Find the area of the ground (in $m^2$).

The maximum area of a triangle inscribed in a semicircle with diameter $30 \, cm$ is $\ldots \ldots \ldots \, cm^{2}$.

An umbrella has $8$ ribs which are equally spaced. Assuming the umbrella to be a flat circle with radius $56 \, cm$,the area between two consecutive ribs is $\ldots \ldots \ldots \, cm^{2}$.

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 $cm^2$)

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

In the figure,$ABC$ is a quadrant of a circle of radius $14 \, cm$ and a semicircle is drawn with $BC$ as diameter. Find the area of the shaded region. (in $cm^2$) [Use $\pi = \frac{22}{7}$]