The slant height of the cone when its radius is 3 cm and height is 4 cm

A sector of radius $12 centimetres$ and central angle $120°$ is rolled up into a cone. Find the radius and height of the cone.

A sector of radius $12 centimetres$ and central angle $120°$ is rolled up into a cone. What is the slant height of the cone?

A rectangular plot is of length $28$ m and width $14$ m. A conical pit of diameter $7$ m and depth $3$ m with its flat surface upward and vertex downward is dug at one corner of the plot. The soil dug out is spread uniformly over the remaining area of the plot. The best approximation value of the increment in the level of the remaining plot is (take $\pi =\frac{22}{7}$)

A cone, hemisphere and cylinder stand on equal bases and have the same height then the ratio of their volumes is _____.
 

Radius of a cylinder is equal to its height. If the radius is taken as ‘$r$’, the volume of the cylinder is $\mathrm{\pi }{r}^2\times r=\mathrm{\pi }{r}^3$. Like this find the volumes of the solids, with the following measures.

A solid metal sphere of radius $6 \mathrm{cm}$ is melted and recast into solid cones of radius $6 \mathrm{cm}$ and height $6 \mathrm{cm}$. Find the number of cones.