7. A cylindrical bucket, 32 cm high and with radius of base 18 cm, 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.

Answers (1)

According to question volume will remain constant thus we can write :

The volume of bucket    =    Volume of heap formed.

                  \pi r^2_1h_1\ =\ \frac{1}{3}\pi r^2_2 h_2      

Let the radius of heap be r.

  \pi\times 18^2 \times 32\ =\ \frac{1}{3}\times \pi \times r^2\times 24

 r\ =\ 18\times 2\ =\ 36\ cm

And thus the slant height will be         

 l\ =\ \sqrt{r^2\ +\ h^2}

     =\ \sqrt{36^2\ +\ 24^2}

     =\ 12\sqrt{13}\ cm

Hence the radius of heap made is 36 cm and its slant height is  12\sqrt{13}\ cm.