Two cones with the same base radius $8\, cm$ and height $15\, cm$ are joined together along their bases. Find the surface area of the shape so formed. (in $cm^2$)

$A$ solid piece of iron in the form of a cuboid of dimensions $49 \, cm \times 33 \, cm \times 24 \, cm$ is moulded to form a solid sphere. The radius of the sphere is (in $cm$):

$A$ cylindrical bucket of height $32 \,cm$ and base radius $18 \,cm$ is filled with sand. This bucket is emptied on the ground and a conical heap of sand is formed. If the height of the conical heap is $24 \,cm$,find the radius and slant height of the heap.

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

The capacity of a cylindrical tank with radius $1.4 \, m$ and height $4 \, m$ is $\ldots \ldots \ldots$ litres.

The $TSA$ (Total Surface Area) of a hemisphere with a diameter of $10 \, cm$ is $\ldots \ldots \ldots \, cm^2$. (in $\pi$)