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9.Straight Line
hard
Let the equations of two adjacent sides of a parallelogram $A B C D$ be $2 x-3 y=-23$ and $5 x+4 y$ $=23$. If the equation of its one diagonal $AC$ is $3 x +$ $7 y=23$ and the distance of A from the other diagonal is $d$, then $50 d ^2$ is equal to $........$.
A
$528$
B
$526$
C
$529$
D
$527$
(JEE MAIN-2023)
Solution

$A$ and $C$ point will be $(-4,5)$ and $(3,2)$ mid point of $AC$ will be $\left(-\frac{1}{2}, \frac{7}{2}\right)$ equation of diagonal $BD$ is
$y-\frac{7}{2}=\frac{\frac{7}{2}}{-\frac{1}{2}} \quad\left(x+\frac{1}{2}\right)$
$7 x+y=0$
Distance of $A$ from diagonal $BD$
$= d =\frac{23}{\sqrt{50}}$
$50 d ^2=(23)^2$
$50 d ^2=529$
Standard 11
Mathematics