$2$ cubes,each of side $12\, cm$,are joined end-to-end. The surface area of the resulting cuboid is...........$cm^2$.

The base of a $10\, cm$ high solid cylinder is a semi-circle of radius $7\, cm$. Its total surface area (in $cm^2$) is (Use $\pi = \frac{22}{7}$)

$A$ cylindrical iron rod is $70\, cm$ long. The diameter of its end portion is $2\, cm$. What is its weight,reckoning a $cm^3$ of iron to weigh $10\, grams$? (in $kg$)

$A$ cubic metre of silver weighing $900\, Kg$ is rolled into a $16\, m$ long square bar. Find out the weight of an exact cube cut off from it.

The diameter of a copper sphere is $18 \, cm$. The sphere is melted and drawn into a long wire of uniform circular cross-section. If the length of the wire is $108 \, m$,the diameter of the wire is ....... $cm$.

If each edge of a cube is increased by $50 \%$,the percentage increase in its surface area is (in $\%$)