Straight Line Question 368

Question: The ends of the base of an isosceles triangle are at $ (2a,\ 0) $ and $ (0,\ a). $ The equation of one side is $ (lx+my)(a+b)=(l+m)\ ab $ The equation of the other side is

Options:

A) $ x+2y-a=0 $

B) $ x+2y=2a $

C) $ 3x+4y-4a=0 $

D) $ 3x-4y+4a=0 $

Show Answer

Answer:

Correct Answer: D

Solution:

  • Obviously, other line AB will pass through (0, a) and $ (2a,k) $ . But as we are given $ AB=AC $

$ \Rightarrow k=\sqrt{4a^{2}+{{(k-a)}^{2}}} $ Þ $ k=\frac{5a}{2} $ Hence the required equation is $ 3x-4y+4a=0 $ .