The radius of a wheel is $21 \, cm$. What is the distance (in $cm$) travelled by the wheel in $10$ revolutions?

$A$ conical cup is filled with ice cream. The ice cream forms a hemispherical shape on its open top. The radius of the hemispherical part is $7 \, cm$. The radius of the hemispherical part equals the height of the cone. Then the volume of the ice cream is $...... cm^3$. $\left[\pi=\frac{22}{7}\right]$

$A$ hemispherical bowl is filled to the brim with a beverage. The contents of the bowl are transferred into a cylindrical vessel whose radius is $50 \%$ more than its height. If the diameter is same for both the bowl and the cylinder,the volume of the beverage in the cylindrical vessel is.........$\%$

If the surface areas of two spheres are in the ratio $4:9,$ then the ratio of their volumes will be

The radius of the base of a solid cylinder is $r \text{ cm}$ and its height is $3 \text{ cm}$. It is recast into a cone of the same radius. The height of the cone will be (in $\text{cm}$):

The slant height of a right circular cone is $10 \, m$,and its height is $8 \, m$. Find the area of its curved surface (in $\pi \, m^2$).