The adjacent sides of a parallelogram are $10 \mathrm{m}$ and $8 \mathrm{m}$. If the distance between the longer sides is $4 \mathrm{m},$ find the distance between the shorter sides.

Find the area of the trapezium whose:

bases$=15 \mathrm{cm}$ and $20 \mathrm{cm}$ and altitude $=8 \mathrm{cm}$

Find the area of the trapezium whose:

bases$=10 \mathrm{cm}$ and $12 \mathrm{cm}$ and altitude $=5 \mathrm{cm}$

Find the area of the given figure.