Question

The latus rectum of a parabola whose directrix is x + y – 2 = 0 and focus is (3, -4), is

• A. $-3\sqrt{2}$
• B. $3\sqrt{2}$
• C. $-3\sqrt{2}$
• D. $\frac{3}{\sqrt{2}}$

Answer 1

The correct option is B $3\sqrt{2}$

Distance between focus and directrix is $=\left|\frac{3-4-2}{\sqrt{2}}\right|=\frac{3}{\sqrt{2}}$
Hence latus rectum $=3\sqrt{2}$
(Since latus rectum is two times the distance between focus and directrix).