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9.Straight Line
normal
The equation of base $BC$ of an equilateral triangle is $3x + 4y = 1$ and vertex is $(-3,2),$ then the area of triangle is-
A
$\frac{4\sqrt 3}{75}$
B
$\frac{4}{5\sqrt 3}$
C
$\frac{8\sqrt 3}{75}$
D
$\frac{16\sqrt 3}{25}$
Solution

$\mathrm{CM}=\frac{|-9+8-1|}{5}=\frac{2}{5}$
Now ${\rm{AC}} = \frac{2}{5}\cos ec{60^\circ } = \frac{4}{{5\sqrt 3 }}$
$\therefore {\mathop{\rm area}\nolimits} (\Delta {\rm{ABC}}) = \frac{{\sqrt 3 }}{4} \cdot \frac{{16}}{{25 \times 3}} = \frac{{4\sqrt 3 }}{{75}}$
Standard 11
Mathematics