The length of a diagonal of a square inscribed in a circle with radius $10\, cm$ is $\ldots \ldots \ldots . cm$.

In the given diagram,the shaded portion represents a flower bed in a plot. If $m \angle O = 90^\circ$,$OB = 21 \, \text{m}$,and $OD = 14 \, \text{m}$,find the area of the flower bed in $\text{m}^2$.

The length of the minute hand of a clock is $14\, cm$. The area of the region swept by it in $10$ minutes is $\ldots \ldots \ldots \, cm^2$.

Which of the following correctly matches the information given in Part $I$ and Part $II$?

Part $I$	Part $II$
$1.$ Formula to find the length of a minor arc	$a.$ $C=2\pi r$
$2.$ Formula to find the area of a minor sector	$b.$ $A=\pi r^{2}$
$3.$ Formula to find the area of a circle	$c.$ $l=\frac{\pi r \theta}{180}$
$4.$ Formula to find the circumference of a circle	$d.$ $A=\frac{\pi r^{2} \theta}{360}$

In a circle,the ratio of the areas of two distinct minor sectors is $1:4$. Then,the ratio of the angles at the centre for those minor sectors is $\ldots \ldots \ldots \ldots$.

In the figure,a circle is inscribed in a square of side $5 \, cm$ and another circle is circumscribing the square. Is it true to say that the area of the outer circle is two times the area of the inner circle? Give reasons for your answer.