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

The total surface area of a cone whose radius is $\frac{r}{2}$ and slant height is $2l$ is

$A$ metallic ball of radius $9 \,cm$ is melted and recast into three metallic balls. If the radii of two balls are $1 \,cm$ and $6 \,cm$,find the radius of the third ball (in $cm$).

The radius of the base of a cone is $14 \, cm$ and its slant height is $50 \, cm$. Find the volume of the cone (in $cm^3$).

$A$ heap of wheat is in the form of a cone whose diameter is $42 \, m$ and height is $20 \, m$. The heap is to be covered by canvas to protect it from rain. If the price of canvas is $₹ 75$ per $m^2$,find the cost of the canvas required.

$A$ small village,having a population of $5000$,requires $75$ litres of water per head per day. The village has an overhead tank of measurement $40 \, m \times 25 \, m \times 15 \, m$. For how many days will the water of this tank last?