Question

please solve this question

Answer 1

take triangles ADE, ABC is similar and find values of AD, DE and AB.

find volume of whole cone which is

:

$\pi {r}^{2}h \frac{1}{2}$

find volume of upper part which had removed from cone to form frustum which is:

$\pi {r}^{2} h \frac{1}{54}$

subtract the volume of upper part of cone from volume of whole cone. By doing this we will get the volume of frustum we want to prove the question.

I hope it will help you.