Find the area of the trapezium in the given figure below:

Given, the parallel sides of the trapezium are 4 cm and 8 cm respectively.

Sum of parallel sides of the trapezium = 4 + 8 = 12 cm.

Height of the trapezium = 5 cm.

Area of the trapezium = $\frac{1}{2}$x (Sum of parallel sides) x (height). 

$\begin{array}{rcl} & =& \frac{1}{2}\times 12\times 5\\ & =& 30 {\mathrm{cm}}^2\end{array}$

Therefore, the area of the trapezium is 30 cm².