Volume of a Right Circular Cone

Q.

A cone is $8.4cm$ high and the radius of its base is $2.1cm.$ It is melted and recast into a sphere. The radius of the sphere is

A) $4.2cm$

B) $2.1cm$

C) $2.4cm$

D) $1.6cm$

Q.

A conical pit of top diameter $3.5\mathrm{m}$ is $12\mathrm{m}$ deep.

What is its capacity in $\mathrm{kilolitres}$?

Q.

The height and radius of a cone is 6 cm and 3 cm respectively .The volume of cone is equal to___$\pi {cm}^3$.

Q. The area of a ring is $40\pi {\text{cm}}^2$. If the width of the ring is $4$ cm, then the sum of the radii of circles

1. $5$
2. $3$
3. $10$
4. $4$

Q. A lead ball of radius $24$ cm is melted down and recast into smaller balls of radius $6$ cm. Assuming that no metal is lost in this process, number of complete smaller balls that can be made, is -

1. $4$
2. $64$
3. $36$
4. $16$

Q. A cone whose height is $15$ cm and radius of base is $6$ cm, is trimmed sufficiently to reduce it to a pyramid whose base is an equilateral triangle. The volume of the portion of removed is

1. $325c{m}^3$
2. $328c{m}^3$
3. $320c{m}^3$
4. $332c{m}^3$