What is the area (in $cm^2$) of a square inscribed in a circle of radius $8 \, cm$?

$A$ running track is in the shape of a circular ring. The difference of its outer circumference and inner circumference is $44\,m$. Then,the width of the track is $\ldots \ldots \ldots \ldots\,m$.

With the vertices $A, B$ and $C$ of a triangle $ABC$ as centres,arcs are drawn with radii $5 \, cm$ each as shown in the figure. If $AB = 14 \, cm, BC = 48 \, cm$ and $CA = 50 \, cm$,then find the area of the shaded region. (Use $\pi = 3.14$) (in $cm^2$)

In a circle with radius $50 \, cm$,the area of the sector formed by a $20 \, cm$ long arc is $\ldots \ldots \ldots cm^2$.

The diagram below is formed by three semicircles. If $OA = OB = 70\, cm,$ find the area of the figure formed (in $cm^2$).

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 $cm^{2}$)