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

The slant height of a cone with radius $6 \, cm$ and height $8 \, cm$ is $\ldots \ldots \ldots \ldots cm$.

The volume of a sphere is $\ldots \ldots \ldots$

The volume of a sphere with diameter $10 \, cm$ is $\ldots \ldots \, cm^3$.

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 $cm^2$)

The curved surface area of a cone with radius $12 \, cm$ and slant height $20 \, cm$ is ....... $\pi \, cm^2$.