If two solid hemispheres of same base radius $r$ are joined together along their bases, then the curved surface area of this new solid is (in $\pi r^{2}$)

The radius and the height of a cylinder are $28 \, cm$ and $54.5 \, cm$ respectively. It is closed at one end by a hemisphere and at the other end by a $21 \, cm$ high cone. Find the total surface area of the combined article. (in $cm^2$)

$A$ plumbline (sahul) is the combination of (see figure):

The slant height of a cone with a hemispherical base is $5 \, cm$. If the total surface area of the article is $103.62 \, cm^2$,find its total height. $(\pi = 3.14)$ (in $cm$)

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

The $TSA$ (Total Surface Area) of a $5$-rupee coin is given by the formula $\ldots \ldots \ldots . .$