If the volume of a sphere is numerically equal to its surface area,then its diameter is ......... $cm$.

$A$ cylinder with base radius of $8\, cm$ and height of $2\, cm$ is melted to form a cone of height $6\, cm.$ The radius of the cone will be (in $cm$):

$A$ spherical aquarium can accommodate $11$ fishes,and each fish requires $1.54 \, m^3$ of water. What is the volume of the aquarium? (in $m^3$)

The radius of the base of a solid cone is $9\, cm$ and its height is $21\, cm$. It is cut into $3$ parts by two cuts which are parallel to its base. The cuts are at heights of $7\, cm$ and $14\, cm$ from the base respectively. What is the ratio of the curved surface areas of the top,middle,and bottom parts respectively?

If the area of the base,height,and volume of a right prism are $(3 \sqrt{3} / 2) P^{2} \, \text{cm}^{2}$,$100 \sqrt{3} \, \text{cm}$,and $7200 \, \text{cm}^{3}$ respectively,then the value of $P$ is?

$A$ rectangular water tank has dimensions $80\, m \times 40\, m$. Water flows into it through a pipe with an opening area of $40\, cm^{2}$ at a speed of $10\, km/hr$. By how much will the water level rise in the tank in half an hour (in $cm$)?