Find the volume of a hemisphere with a diameter of $12 \, cm$. (Use $\pi = 3.14$) (in $cm^3$) (in $.16$)

Find the volume of a sphere whose surface area is $1256 \, cm^{2}$. (Use $\pi = 3.14$)

$A$ cylindrical tube open at both ends is made of an iron sheet which is $2 \, cm$ thick. If the outer diameter is $16 \, cm$ and its length is $100 \, cm$, find how many cubic centimeters of iron have been used in making the tube? (in $cm^3$)

In the auditorium,there are $20$ cylindrical pillars. Each pillar has a radius of $14 \, cm$ and a height of $5 \, m$. Find the cost of painting the curved surface of all the pillars at the rate of ₹ $120$ per $m^2$.

The surface area of a sphere and the curved surface area of a hemisphere are equal. Find the ratio of their radii.

The surface area and volume of a cube with an edge length of $x \ cm$ are numerically equal. Find the value of $x$.