Surface area of a sphere $= \ldots \ldots.$

Write True or False and justify your answer: The volume of a sphere is equal to two-thirds of the volume of a cylinder whose height and diameter are equal to the diameter of the sphere.

The total surface area of a cone is equal to:

Curved surface area of a hemisphere $= \ldots \ldots \ldots$

$A$ cuboidal box measures $25 \, cm \times 15 \, cm \times 8 \, cm$. Find its total surface area (in $cm^2$).

The slant height of a cone is $25 \,cm$ and its curved surface area is $550 \,cm^{2}$. Find the radius,height,and the total surface area of the cone.