Q. Two tangents to the circle $x^{2} + y^{2} = 4$ at the points $A$ and $B$ meet at$p( - 4,\ 0)$. The area of the quadrilateral $PAOB$, where $O$ is the origin, is

A) 4 sq units
B) $6\sqrt{2}$ sq units
C) $4\sqrt{3}$ sq units
D) None of these
Explanation

(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

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.

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