Straight Line Question 68
Question: If the equation of base of an equilateral triangle is $ 2x-y=1 $ and the vertex is (?1, 2), then the length of the side of the triangle is [Kerala (Engg.) 2005]
Options:
A) $ \sqrt{\frac{20}{3}} $
B) $ \frac{2}{\sqrt{15}} $
C) $ \sqrt{\frac{8}{15}} $
D) $ \sqrt{\frac{15}{2}} $
Correct Answer: A $ AD=| \frac{-2-2-1}{\sqrt{{{(2)}^{2}}+{{(-1)}^{2}}}} |=| \frac{-5}{\sqrt{5}} |=\sqrt{5} $ $ \because $ $ \tan 60^{o} $ $ =\frac{BD}{AD}\Rightarrow \sqrt{3}=\frac{\sqrt{5}}{BD} $
Þ $ BD=\sqrt{\frac{5}{3}} $ $ \therefore $ $ BC=2BD=2\sqrt{\frac{5}{3}}=\sqrt{\frac{20}{3}} $ .
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Answer:
Solution:
BETA
