The equation of the line joining the centroid with the orthocentre of the triangle formed by the points $(-2…

The equation of the line joining the centroid with the orthocentre of the triangle formed by the points $(-2,3),(2,-1),(4,0)$ is
  1. $x+y-2=0$
  2. $11 x-y-14=0$
  3. $x-11 y+6=0$
  4. $2 x-y-2=0$

Solution

Let $A D$ and $B E$ are altitudes of the triangle. $\therefore$ Equation of $A D$ is given by $ \begin{aligned} y-3 & =\frac{-1}{\text { Slope of } B C}(x+2) \\ \Rightarrow \quad y-3 & =\frac{-1}{\left(\frac{0+1}{4-2}\right)}(x+2) \\ y-3 & =-2(x+2 \\ y-3 & =-2 x-4 \\ \Rightarrow \quad 2 x+y+1 & =0 \end{aligned} $ $\therefore$ Equation of $B E$ is given by $ \begin{aligned} & y+1=\frac{-1}{\text { Slope of } A C}(x-2) \Rightarrow y+1=\frac{-1}{\left(\frac{0-3}{4+2}\right)}(x-2) \\ & y+1=2(x-2) \\ & y+1=2 x-4 \\ & \Rightarrow \quad y=2 x-5 \end{aligned} $ Since, orthocentre is the intersecting point of altitudes. $\therefore$ On solving Eqs. (i) and (ii), we get orthocentre $(1,-3)$. Also, centroid of $\triangle A B C=\left(\frac{-2+2+4}{3}, \frac{3-1+0}{3}\right)$ $ =\left(\frac{4}{3}, \frac{2}{3}\right) $ $\therefore$ Equation of line joining $(0,-1)$ and $\left(\frac{4}{3}, \frac{2}{3}\right)$ is $\begin{aligned} & y+3=\frac{\frac{2}{3}+3}{\frac{4}{3}-1}(x-1) \\ & \Rightarrow \quad y+3=11(x-1) \\ & \Rightarrow \quad y+3=11 x-11 \\ & \Rightarrow \quad 11 x-y-14=0 . \\ \end{aligned}$

Asked in: AP EAMCET 2018 (22 Apr Shift 1)

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