Skip to main content
Back to Properties of Triangle
JEE Main 2024
Properties of Triangle
Properties of Triangle
Hard

Question

Two vertices of a triangle ABC\mathrm{ABC} are A(3,1)\mathrm{A}(3,-1) and B(2,3)\mathrm{B}(-2,3), and its orthocentre is P(1,1)\mathrm{P}(1,1). If the coordinates of the point C\mathrm{C} are (α,β)(\alpha, \beta) and the centre of the of the circle circumscribing the triangle PAB\mathrm{PAB} is (h,k)(\mathrm{h}, \mathrm{k}), then the value of (α+β)+2( h+k)(\alpha+\beta)+2(\mathrm{~h}+\mathrm{k}) equals

Options

Solution

mPA=22=1mBC=1\begin{aligned} & m_{P A}=\frac{2}{-2}=-1 \\ & \therefore \quad m_{B C}=1 \end{aligned} BC:y=x+5mBP=23=23mAC=32AC:y=32x1122y=3x11C:(21,26)\begin{aligned} & B C: y=x+5 \\ & m_{B P}=\frac{2}{-3}=\frac{-2}{3} \\ & \therefore m_{A C}=\frac{3}{2} \\ & A C: y=\frac{3}{2} x-\frac{11}{2} \quad \Rightarrow 2 y=3 x-11 \\ & \therefore \quad C:(21,26) \end{aligned} Let the circumcentre be (h,k)(h, k) (h1)2+(k1)2=(h+2)2+(k3)2... (i)(h1)2+(k1)2=(h3)2+(k+1)2... (ii)\begin{aligned} & (h-1)^2+(k-1)^2=(h+2)^2+(k-3)^2 \quad \text{... (i)}\\ & (h-1)^2+(k-1)^2=(h-3)^2+(k+1)^2 \quad \text{... (ii)} \end{aligned} Solving (i) and (ii) h=192,k=232α+β+2(h+k)=21+261923=2+3=5\begin{aligned} & h=\frac{-19}{2}, k=\frac{-23}{2} \\ & \alpha+\beta+2(h+k) \\ & =21+26-19-23 \\ & =2+3=5 \end{aligned}

Practice More Properties of Triangle Questions

View All Questions