The curved surface area $(CSA)$ of a cone is $\ldots \ldots$

Volume of a cone $= \dots$

The base of a cone with radius $15 \, cm$ and height $20 \, cm$ is hemispherical. Find the total surface area of this article. $(\pi = 3.14)$ (in $cm^2$) (in $.5$)

The base of a cone with radius $7\, cm$ and height $24\, cm$ is hemispherical. Find the cost of painting its surface at the rate of ₹ $2/cm^2$. (in ₹)

The shape of a lump of jaggery is that of a frustum of a cone. Its radii are $14 \, cm$ and $7 \, cm$ and height is $12 \, cm$. Find the volume of the lump of jaggery (in $cm^3$).

Write 'True' or 'False' and justify your answer:
$A$ solid cylinder of radius $r$ and height $h$ is placed over another cylinder of the same height and radius. The total surface area of the shape so formed is $4 \pi r h + 4 \pi r^2$.