Find the total surface area of a hemisphere of radius $42 \, cm$. (in $cm^2$)

The dimensions of a cuboid are in the ratio of $4: 3: 1$. If its total surface area is $3800 \, cm^{2}$,then find its volume in $cm^{3}$.

The radius of the base of a cone is $14 \, cm$ and its slant height is $50 \, cm$. Find the volume of the cone (in $cm^3$).

The length of a metal hollow cylinder is $70\, cm$. If the radius of the hollow inside it is $10\, cm$ and the metal thickness is $1\, cm$,find the difference between the areas of the outer and inner curved surfaces.

The edge of a cube is $16\, cm$. Find the total surface area of the cube (in $cm^2$).

Curved surface area of a cone $= \dots$