If $210\, m^{3}$ of sand is thrown into a tank $12\, m$ long and $5\, m$ wide,find how much the water level will rise? (in $m$)

If the radius of a cylinder is doubled and the height is halved,then what would be the ratio between the new curved surface area and the previous curved surface area of the cylinder?

$A$ cone,a hemisphere,and a cylinder stand on equal bases and have the same height. The ratio of their volumes is:

Find the curved surface area (in $cm^{2}$) of a hemisphere of diameter $28\, cm$.

The diagonal of a cubical box is $\sqrt{300} \text{ cm}$. Find out the surface area.

$A$ right circular cone is exactly fitted inside a cube in such a way that the edges of the base of the cone are touching the edges of one of the faces of the cube and the vertex is on the opposite face of the cube. If the volume of the cube is $343 \, c.c.$,then what approximately is the volume of the cone? (in $c.c.$)