If $\theta$ is the angle (in degrees) of a sector of a circle of radius $r$,then the area of the sector is:

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

In a circle with radius $r$,the area of a sector formed by an arc of length $l$ is.........

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

Find the area of the shaded region in the figure where arcs drawn with centers $A, B, C,$ and $D$ intersect in pairs at mid-points $P, Q, R,$ and $S$ of the sides $AB, BC, CD,$ and $DA,$ respectively of a square $ABCD$ (Use $\pi = 3.14$) (in $cm^{2}$).

As shown in the diagram,$\overline{ OA }$ and $\overline{ OB }$ are two radii of $\odot( O , 21 \text{ cm} )$ perpendicular to each other. If $OD = 10 \text{ cm}$,find the area of the shaded region. (in $\text{cm}^2$)