The height of a wall is six times its width,and the length of the wall is seven times its height. If the volume of the wall is $16128 \, m^3$,its width is ...... $m$.

If a solid cone of volume $27\, \pi\, cm^3$ is kept inside a hollow cylinder whose radius and height are the same as that of the cone,then the volume of water needed to fill the empty space is...........$\pi\, cm^3$.

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 can with a horizontal base and an internal radius of $3.5 \, cm$ contains sufficient water so that when a solid sphere is placed inside,the water just covers the sphere. The sphere fits exactly into the can. The depth of the water in the can before the sphere was added is:

$A$ cone of height $7 \text{ cm}$ and base radius $3 \text{ cm}$ is carved from a rectangular block of wood $10 \text{ cm} \times 5 \text{ cm} \times 2 \text{ cm}$. The percentage of wood wasted is:

The radii of two solid iron spheres are $1 \, cm$ and $6 \, cm$ respectively. $A$ hollow sphere is made by melting the two spheres. If the external radius of the hollow sphere is $9 \, cm$,then its thickness (in $cm$) is