Straight Line and Pair of Straight Lines 1 Question 30
30.
If $A _0, A _1, A _2, A _3, A _4$ and $A _5$ be a regular hexagon inscribed in a circle of unit radius. Then, the product of the lengths of the line segments $A _0 A _1, A _0 A _2$ and $A _0 A _4$ is
(a) $3 / 4$
(b) $3 \sqrt{3}$
(c) $3$
(d) $\frac{3 \sqrt{3}}{2}$
$(1998,2 M)$
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Answer:
Correct Answer: 30. (c)
Solution:
- Now, $\left(A _0 A _1\right)^{2}=(1-\frac{1}{2})^{2}+(0-\frac{\sqrt{3}}{2})^{2}$
$ \begin{aligned} & \quad\left(A _0 A _2\right)^{2}=(1+\frac{1}{2})^{2}+(0-\frac{\sqrt{3}}{2})^{2} \\ &=(\frac{3}{2})^{2}+(-\frac{\sqrt{3}}{2})^{2}=\frac{9}{4}+\frac{3}{4}=\frac{12}{4}=3 \\ & \Rightarrow \quad A _0 A _2=\sqrt{3} \\ & \text { and } \quad\left(A _0 A _4\right)^{2}=(1+\frac{1}{2})^{2}+(0+\frac{\sqrt{3}}{2})^{2} \\ &=(\frac{3}{2})^{2}+(\frac{3}{4})=\frac{9}{4}+\frac{3}{4}=\frac{12}{4}=3 \\ & \Rightarrow \quad A _0 A _4=\sqrt{3} \\ & \text { Thus, } \quad\left(A _0 A _1\right)\left(A _0 A _2\right)\left(A _0 A _4\right)=3 \end{aligned} $
