The area of the base of a cylinder is equal to:

$A$ sphere and a solid hemisphere have equal radii. Then,the ratio of the surface area of the sphere and $TSA$ of the hemisphere is $\ldots \ldots \ldots \ldots$

Write 'True' or 'False' and justify your answer:
If a solid cone of base radius $r$ and height $h$ is placed over a solid cylinder having the same base radius and height as that of the cone,then the curved surface area of the shape is $\pi r \sqrt{h^{2} + r^{2}} + 2 \pi r h$.

$A$ cylinder is closed at both the ends by $28 \, cm$ high cones. The radius and the height of the cylinder are $21 \, cm$ and $50 \, cm$ respectively. Find the total surface area of the article in $cm^2$.

The base of a cone is in the shape of a ..............

Total Surface Area of a cone $= \dots$