A cylindrical bucket, 32 cm high and 18 cm of radius of the base, is filled with sand. This bucket is emptied on the ground and a conical heap of sand is formed. If the height of the conical heap is 24 cm, find the radius and slant height of the heap
The height and radius of the cylindrical bucket are $h=32 \mathrm{~cm}$ and $r=18 \mathrm{~cm}$ respectively. Therefore, the volume of the cylindrical bucket is
$V=\pi r^{2} h$
$=\frac{22}{7} \times(18)^{2} \times 32$
The bucket is full of sand and is emptied in the ground to form a conical heap of sand of height $h_{1}=24 \mathrm{~cm}$. Let, the radius and slant height of the conical heap be $r_{1} \mathrm{~cm}$ and $l_{1} \mathrm{~cm}$ respectively. Then, we have
$l_{1}^{2}=r_{1}^{2}+h_{1}^{2}$
$\Rightarrow r_{1}^{2}=l_{1}^{2}-h_{1}^{2}$
$\Rightarrow r_{1}^{2}=l_{1}^{2}-(24)^{2}$
The volume of the conical heap is
$V_{1}=\frac{1}{3} \pi r_{1}^{2} h_{1}$
$=\frac{1}{3} \times \frac{22}{7} \times r_{1}^{2} \times 24$
$=\frac{22}{7} \times r_{1}^{2} \times 8$
Since, the volume of the cylindrical bucket and conical hear are same, we have
$V_{1}=V$
$\Rightarrow \frac{22}{7} \times r_{1}^{2} \times 8=\frac{22}{7} \times(18)^{2} \times 32$
$\Rightarrow \quad r_{1}^{2}=(18)^{2} \times 4$
$\Rightarrow \quad r_{1}=18 \times 2$
$\Rightarrow \quad r_{1}=36$
Then, we have
$l_{1}^{2}=r_{1}^{2}+h_{1}^{2}$
$\Rightarrow l_{1}^{2}=(36)^{2}+(24)^{2}$
$\Rightarrow l_{1}=43.27$
Therefore, the radius and the slant height of the conical heap are 36 cm and 43.27 cm respectively.