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 $\ldots \ldots \ldots \ldots$.

The length of the minute hand of a clock is $7\,cm$. The area of the region swept by it in $20$ minutes is $\ldots \ldots \ldots \,cm^2$.

Find the diameter of the circle whose area is equal to the sum of the areas of the two circles of diameters $20 \, cm$ and $48 \, cm$. (in $cm$)

Find the difference of the areas of a sector of angle $120^{\circ}$ and its corresponding major sector of a circle of radius $21 \, cm$. (in $cm^2$)

$A$ piece of wire $20 \,cm$ long is bent into the form of an arc of a circle subtending an angle of $60^{\circ}$ at its centre. Find the radius of the circle. (in $cm$)

As shown in the diagram,the side length of square garden $ABCD$ is $60\, m$. Flower beds are prepared in the shape of circular segments on two opposite sides of the square. The centre of the circles for these segments is the point of intersection $O$ of the diagonals of square $ABCD$. Find the total area of the two flower beds. (Use $\pi=3.14$) (in $m^2$)