Curved surface area of a cone $= \dots$

The radius and slant height of a cone are $10 \, cm$ and $25 \, cm$ respectively. Find the total surface area of a cone. (in $cm^2$)

Write True or False and justify your answer.
$A$ right circular cylinder just encloses a sphere of radius $r$ as shown in the figure. The surface area of the sphere is equal to the curved surface area of the cylinder.

If the edge of a cube is $7\, cm$,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.

The surface area of a sphere is $7850 \, cm^2$. Find its radius in $cm$. (Use $\pi = 3.14$)