During the conversion of a solid from one shape to another,the volume of the new shape will

The area of the base of a cone is $60 \, cm^{2}$ and its height is $15 \, cm$. Then,the volume of the cone is $\ldots \ldots \ldots \, cm^{3}$.

The radii of three metallic spheres are $3 \, cm$,$4 \, cm$,and $5 \, cm$. These spheres are melted and recast into a single new sphere. Find the radius of the new sphere (in $cm$).

The base of a cone with radius $15\, cm$ and slant height $25\, cm$ is hemispherical. Find the volume of this solid. $(\pi=3.14)$ (in $cm^{3}$)

$A$ cylinder is closed at both ends by $40 \, cm$ high cones. The radius of the cylinder is $30 \, cm$ and the total height of the article is $180 \, cm$. Find the total surface area of the article. $(\pi = 3.14)$ (in $cm^2$)

$A$ heap of rice is in the form of a cone of diameter $9 \, m$ and height $3.5 \, m$. Find the volume of the rice. How much canvas cloth is required to just cover the heap?