The area of trapezium is $384 {\mathrm{cm}}^2$ its parallel sides are in the ratio $5:3$ and the distance between them is $12 \mathrm{cm}$. The length of the longer parallel side is

Area of triangle$=\frac{1}{2}\times \left(\_\_\_\_\_\right)\times \left(\_\_\_\_\_\right)$

The parallel sides of a trapezium are $14 \mathrm{cm}$ and $18 \mathrm{cm}$ and the distance between them is $8 \mathrm{cm}$. The area of the trapezium is _____ ${\mathrm{cm}}^2$.