The surface area of a cube whose edge is $a$ is: (in $a^{2}$)

The total surface area of a hemisphere is $4158 \, cm^2$. Find its diameter in $cm$.

$A$ cylindrical container of radius $14\, cm$ is partially filled with water. $A$ solid cuboid of iron with dimensions $22\, cm \times 16\, cm \times 7\, cm$ is submerged in it. Find the rise in the level of the water when the solid is completely submerged. (in $cm$)

The length,breadth,and height of a cuboid are $20\, cm$,$15\, cm$,and $12\, cm$ respectively. Find its total surface area (in $cm^2$).

The radius and slant height of a conical vessel are $35 \,cm$ and $91 \,cm$ respectively. What is its capacity in litres (in $.8$)?

The edge of a cube is $6 \, cm$. Find the total surface area of the cube and the volume of the cube.