Question

If $(0,0)$ be the vertex and $3x-4y+2=0$ be the directrix of a parabola, then the length of its latus rectum is

• A. $4/5$
• B. $2/5$
• C. $8/5$
• D. $1/5$

Answer 1

Answer: (C)

$8/5$

Distance of vertex from directrix = $\frac{\left|3\right(0)-4(0)+2|}{\sqrt{3^2+4^2}}=\frac{2}{5}=a$

Length of latus rectum = $4a=\frac{8}{5}$

$\therefore$ Option C is correct