Question

The point (3,4) is the focus and $2x-3y+5=0$ is the directrix of a parabola .Its latus rectum is

• A. $\frac{2}{\sqrt{13}}$
• B. $\frac{4}{\sqrt{13}}$
• C. $\frac{1}{\sqrt{13}}$
• D. $\frac{3}{\sqrt{13}}$

Answer 1

Answer: (A)

$\frac{2}{\sqrt{13}}$

$4a=2$ (distance from focus to directrix)
$2=\frac{|6-12+5|}{\sqrt{4+9}}=\frac{2}{13}$