The radii of the top and bottom of a bucket of slant height $45 \, cm$ are $28 \, cm$ and $7 \, cm$,respectively. The curved surface area of the bucket is (in $cm^2$)

$A$ metallic spherical shell of internal and external diameters $4 \, cm$ and $8 \, cm$,respectively,is melted and recast into the form of a cone of base diameter $8 \, cm$. The height of the cone is (in $cm$):

The base of a cone with radius $15 \, cm$ and slant height $25 \, cm$ is hemispherical. Find the volume of this solid. $(\pi = 3.14)$ (in $cm^3$)

If the radius of a sphere is doubled,its volume becomes $\ldots \ldots \ldots$ times the volume of the original sphere.

The $CSA$ of a cone with radius $7\, cm$ and slant height $15\, cm$ is $\ldots \ldots \ldots \, cm^2$.

Write 'True' or 'False' and justify your answer:
Total surface area of a lattu (top) as shown in the $Fig.$ is the sum of total surface area of hemisphere and the total surface area of cone.