The area of a square inscribed in a circle of radius $35 \, cm$ is $\ldots \ldots \ldots \ldots cm^{2}$.

In the adjoining diagram, $\overline{ AB }$ and $\overline{ CD }$ are diameters of $\odot( O , 7\, cm )$ perpendicular to each other. $A$ circle is drawn with diameter $\overline{ OD }$. Find the area of the shaded region. (in $cm^2$)

If the perimeter of a circle is equal to that of a square,then the ratio of their areas is

On a square cardboard sheet of area $784 \, cm^{2}$, four congruent circular plates of maximum size are placed such that each circular plate touches the other two plates and each side of the square sheet is tangent to two circular plates. Find the area of the square sheet not covered by the circular plates (in $cm^{2}$).

The maximum area of $\Delta ABC$ inscribed in a semicircle with radius $10 \, cm$ is ....... $cm^2$.

The radius of a circle is $12 \, cm$. Find its circumference and area $(\pi = 3.14)$.