The radii of a frustum of a cone are $10\,cm$ and $7\,cm$. If its height is $4\,cm$, then its curved surface area is $\ldots \ldots \ldots \,cm^2$. (in $\pi$)

Three cubes of a metal whose edges are in the ratio $3:4:5$ are melted and converted into a single cube whose diagonal is $12\sqrt{3} \, \text{cm}$. Find the edges of the three cubes (in $\text{cm}$).

$A$ cylinder with radius $8 \, cm$ and height $9 \, cm$ is surmounted by a cone of height $15 \, cm$. Find the total surface area and the volume of the combined solid.

$A$ building is in the form of a cylinder surmounted by a hemispherical dome (see figure). The base diameter of the dome is equal to $\frac{2}{3}$ of the total height of the building. Find the height of the building,if it contains $67 \frac{1}{21} \, m^3$ of air. (in $m$)

$A$ cone is cut by a plane parallel to its base and the smaller cone formed on the upper side of the plane is removed. The remaining part on the other side of the plane is called:

The curved surface area of a cone is $85 \pi \, cm^{2}$. If its diameter is $10 \, cm$,its slant height is $\dots \dots \dots \dots \, cm$.