Q86 / 150 · MHT CET 2020 (13 Oct Shift 1) · Mathematics
The length of latus rectum of the parabola whose focus is at $(1,-2)$ and directrix is
the line $x+y+3=0$ is
- A$8 \sqrt{2}$ units
- Correct answerB$2 \sqrt{2}$ units
- C$\sqrt{2}$ units
- D$4 \sqrt{2}$ units
Solution
$\hat{f}^{(1,-2)}$
$x+y+3=0$
Distance of focus from
$\text { Dizectrix }=22$
$\begin{array}{l}
1^{2} \text { distance } \\
=\frac{|1-2+3|}{\sqrt{2}} \\
=\sqrt{2} .
\end{array}$
Length of L.R
$=2 \sqrt{2}$
Hence, the correct answer is option: 'B'.