The length of the latusrectum of the parabola $(x-2)^2+(y-3)^2=\frac{1}{25}(3 x-4 y+7)^2$ is

The length of the latusrectum of the parabola $(x-2)^2+(y-3)^2=\frac{1}{25}(3 x-4 y+7)^2$ is
  1. $\frac{1}{5}$
  2. $\frac{2}{5}$
  3. $\frac{3}{5}$
  4. $\frac{4}{5}$

Solution

Given, equation of parabola is $ \begin{aligned} & (x-2)^2+(y-3)^2=\frac{1}{25}(3 x-4 y+7)^2 \\ & \Rightarrow 25\left[(x-2)^2+(y-3)^2\right]=(3 x-4 y+7)^2 \end{aligned} $ Focus of the parabola $=(2,3)$ Equation of directrix $=3 x-4 y+7$ Length of latus rectum is twice the perpendicular distance from focus to directrix. $ L=\frac{2|3 \times 2-4 \times 3+7|}{\sqrt{3^2+(-4)^2}}=2\left[\frac{6-12+7}{5}\right]=\frac{2}{5} $

Asked in: AP EAMCET 2022 (06 Jul Shift 2)

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