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9.Straight Line
normal
Area of the rhombus bounded by the four lines, $ax \pm by \pm c = 0$ is :
A
$\frac{{{c^2}}}{{2\,ab}}$
B
$\frac{{2\,{c^2}}}{{ab}}$
C
$\frac{{4\,{c^2}}}{{ab}}$
D
$\frac{{ab}}{{4\,{c^2}}}$
Solution
The four lines will form a rhombus. The coordinates of the vertices are $\left(-\frac{ c }{ a }, 0\right),\left(\frac{ c }{ a }, 0\right),\left(0, \frac{ c }{ b }\right),\left(0,-\frac{ c }{ b }\right)$
Let $d _1, d _2$ be the diagonals of the rhombus.
$d _1=\frac{2 c }{ a }$
$d _2=\frac{2 c }{ b }$
$\text { Area }=\frac{1}{2} d _1 \cdot d _2=\frac{2 c ^2}{ ab }$
Standard 11
Mathematics