(a)
In $\mathrm{\Delta}POB$,
[image:11_image21.emf]
$\sin\theta = \frac{2}{4} = \frac{1}{2}$
$\Rightarrow \ \ \ \theta = 30{^\circ}$
$\therefore\ \ area(\mathrm{\Delta}POA) = \frac{1}{2} \times 2 \times 4 \times \sin{30{^\circ}} = 2$
Hence, area (quad $PAOB$)=2 area $(\mathrm{\Delta}POA)$
$= 2 \times 2 = 4$ sq units