The side of a square metal sheet is $12 \mathrm{m}$. Four squares each of side $3 \mathrm{m}$ are cut and removed from the four corners of the sheet and the remaining part is folded to form a cuboid (without top face). Find the volume of the cuboid so formed.

The parallel sides of a trapezium $ABCD$ are $16 \mathrm{cm}, 8 \mathrm{cm}$ and the distance between them is $6 \mathrm{cm}$. $AF$ and $BE$ are the perpendiculars drawn to $DC$. Find the total area of the triangles $ADF$ and $BCE$ (in ${\mathrm{cm}}^2$).

Find the area of the shaded part in the figure given below: