The closed figure formed by an arc of a circle and the radii through its end points is called .........

In the figure,$AB$ is a diameter of the circle,$AC = 6 \, cm$ and $BC = 8 \, cm$. Find the area of the shaded region (Use $\pi = 3.14$). (in $cm^2$)

The area of the circle that can be inscribed in a square of side $6 \, cm$ is (in $cm^2$) (in $\pi$)

In $\odot(O, r)$,the length of minor $\widehat{ACB}$ is one-eighth of the circumference of the circle. Then,the measure of the angle subtended at the centre by that arc is $\ldots \ldots \ldots \ldots$ (in $^\circ$)

The formula to find the length of a major arc of a circle is ............

From a circular metallic sheet with radius $21\, cm$,a regular hexagon of side $21\, cm$ is cut off. Find the area of the remaining sheet. $(\sqrt{3} = 1.73)$ (in $cm^2$)