JEE Main & Advanced Mathematics Rectangular Cartesian Coordinates Question Bank Critical Thinking

  • question_answer
    ABC is an isosceles triangle. If the coordinates of the base are B (1,3) and C (- 2, 7), the coordinates of vertex A can be [Orrissa JEE 2002; Pb. CET 2002]

    A) (1, 6)

    B) \[\left( -\frac{1}{2},\,5 \right)\]

    C) \[\left( \frac{5}{6},\,6 \right)\]

    D) None of these

    Correct Answer: C

    Solution :

    The vertex \[A\,(x,\,\,y)\] is equidistant from B and C because ABC is an isosceles triangle. Therefore, \[{{(x-1)}^{2}}+{{(y-3)}^{2}}={{(x+2)}^{2}}+{{(y-7)}^{2}}\] \[\Rightarrow \,\,6x-8y+43=0\] Thus, any point lying on this line can be the vertex A except the mid-point \[\left( -\frac{1}{2},\,\,5 \right)\] of BC.


You need to login to perform this action.
You will be redirected in 3 sec spinner