$1 \, m^{2} = \ldots \ldots \, cm^{2}$

The radii of three metal spheres are $3 \,cm, 4 \,cm$ and $5 \,cm$ respectively. They are melted into a single solid sphere. Find the radius of the new solid sphere (in $cm$).

The slant height of a cone is $25 \,cm$ and its curved surface area is $550 \,cm^{2}$. Find the radius,height,and the total surface area of the cone.

$1$ hectare $= \ldots \ldots \text{ } m^{2}$

The curved surface area of a cylinder is $3960\, cm^{2}$. If its radius is $21\, cm$,find its height in $cm$.

Write True or False and justify your answer in each of the following: If a sphere is inscribed in a cube,then the ratio of the volume of the cube to the volume of the sphere will be $6: \pi$.