Find the diagonal of a cuboid whose dimensions are $12\, m$ by $10\, m$ by $8\, m$.

$A$ cube of edge $3\, cm$ of iron weighs $12\, gm$. What is the weight of a similar cube of iron whose edge is $12\, cm$? (in $gm$)

$A$ solid cone is $25 \ cm$ high and the radius of its base is $50 \ cm$. It is melted and recast into a solid sphere. Determine the surface area of the sphere (in $cm^2$).

$A$ reservoir, $30\, m$ long and $15\, m$ broad, is filled with water. How many gallons of water must be taken out to lower the level of water by $4\, m$? (in gallons)

Three solid spheres have their radii $r_{1}, r_{2}$ and $r_{3}$. The spheres are melted to form a single solid sphere of a bigger radius. The radius of the new sphere is:

Find out the cost of the log of wood measuring $15 \frac{1}{2} \text{ m}$ by $2 \frac{3}{4} \text{ m}$ by $1 \frac{1}{3} \text{ m}$ at ₹ $45$ per $\text{cm}^3$ (in ₹).