The diameter of a solid sphere is $14 \, cm$. Find its surface area in $cm^2$.

The ratio of the radius and slant height of a cone is $3:5$ and its curved surface area is $423.9 \, cm^2$. Find its volume. $(\pi = 3.14)$ (in $cm^3$)

The diameter of a solid hemisphere is $21 \, cm$,then its volume is $\ldots \ldots \ldots \, cm^3$.

Write True or False and justify your answer in each of the following: If the radius of a right circular cone is halved and height is doubled,the volume will remain unchanged.

$A$ hemispherical bowl of radius $18\, cm$ is completely filled with medicine. This medicine is to be filled in cylindrical bottles of radius $2\, cm$ and height $4\, cm$. How many bottles are required to empty the bowl?

Lateral surface area of a cuboid $= \ldots \ldots \ldots$