The area of the circular base of a hemisphere is $154 \, cm^{2}$. Then,its total surface area is $\ldots \ldots \ldots \, cm^{2}$.

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

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

How many cubic centimetres of iron are required to construct an open box whose external dimensions are $36 \, cm$,$25 \, cm$,and $16.5 \, cm$,provided the thickness of the iron is $1.5 \, cm$? If one cubic $cm$ of iron weighs $7.5 \, g$,find the weight of the box.

$A$ plumbline (sahul) is the combination of (see figure):

Three metallic solid cubes whose edges are $3 \, cm$,$4 \, cm$,and $5 \, cm$ are melted and formed into a single cube. Find the edge of the cube so formed (in $cm$).