If two tangents inclined at an angle of 60° are drawn to a circle of radius 3 cm, then the length of each tangent is
(a) 3 cm
(b) $\frac{3 \sqrt{3}}{2} \mathrm{~cm}$
(c) $3 \sqrt{3} \mathrm{~cm}$
(d) 6 cm
(c) $3 \sqrt{3} \mathrm{~cm}$
Given, $\mathrm{PA}$ and $\mathrm{PB}$ are tangents to circle with centre $\mathrm{O}$ and radius $3 \mathrm{~cm}$ and $\angle \mathrm{APB}=60^{\circ}$.
T angents drawn from an external point are equal; so, PA $=$ PB.
And $O P$ is the bisector of $\angle A P B$, which gives $\angle O P B=\angle O P A=30^{\circ}$.
OA $\perp$ PA. So, from right $-$ angled $\Delta$ OPA, we have :
$\frac{\mathrm{OA}}{\mathrm{AP}}=\tan 30^{\circ}$
$\Rightarrow \frac{\mathrm{OA}}{\mathrm{AP}}=\frac{1}{\sqrt{3}}$
$\Rightarrow \frac{3}{\mathrm{AP}}=\frac{1}{\sqrt{3}}$
$\Rightarrow \mathrm{AP}=3 \sqrt{3} \mathrm{~cm}$