The radius and height of a cone are $5\,cm$ and $12\,cm$ respectively. Then,the ratio of its $CSA$ and area of base is $\ldots \ldots \ldots \ldots$

$A$ canal is $300 \,cm$ wide and $120 \,cm$ deep. The water in the canal is flowing with a speed of $20 \,km/h$. How much area will it irrigate in $20 \,minutes$ if $8 \,cm$ of standing water is desired? (in $hectares$)

The radius and the height of a cylinder are $28 \, cm$ and $54.5 \, cm$ respectively. It is closed at one end by a hemisphere and at the other end by a $21 \, cm$ high cone. Find the total surface area of the combined article. (in $cm^2$)

Total surface area of a hemisphere with diameter $2 \, cm$ is $\ldots \ldots \ldots cm^{2}$.

The ratio of the diameters of two cylinders is $3:4$ and the ratio of their heights is $4:5$. Then,the ratio of their volumes is ..... .

The ratio of the radii of two spheres is $3:4$. Then,the ratio of their volumes is $\ldots \ldots \ldots$