The union of a chord of a circle and its corresponding arc is called $\ldots \ldots \ldots \ldots$

The circumference of a circle is $176\,cm$. Then,its radius is $\ldots \ldots \ldots \ldots cm$.

As shown in the diagram,the side length of square $ABCD$ is $35 \, cm$. Two semicircles are drawn on its sides $\overline{AB}$ and $\overline{CD}$ as diameters. Find the area of the shaded region in $cm^2$.

Find the number of revolutions made by a circular wheel of area $1.54 \, m^2$ in rolling a distance of $176 \, m$.

As shown in the diagram,the radii of two concentric circles are $21 \, cm$ and $28 \, cm$. If $m \angle AOB = 40^\circ$,find the area of the shaded region. (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 $cm^{2}$)