BCECE Engineering BCECE Engineering Solved Paper-2003

  • question_answer
    Three points are\[A(6,3),B(-3,5),C(4,-2)\]and \[P(x,y)\]is any point, then the ratio of area of \[\Delta PBC\]and \[\Delta ABC\]is:

    A) \[\frac{x+y-2}{7}\]                          

    B)                   \[\frac{x-y+2}{2}\]                         

    C)                   \[\frac{x-y-2}{7}\]                          

    D)                   none of these

    Correct Answer: A

    Solution :

    Key Idea: If \[A({{x}_{1}},{{y}_{1}}).B({{x}_{2}}{{y}_{2}})\]and \[C({{x}_{3}},{{y}_{3}})\]are the vertices of \[a\]triangle, then Area of \[\Delta =\frac{1}{2}\{{{x}_{1}}({{y}_{2}}-{{y}_{3}})+{{x}_{2}}({{y}_{3}}-{{y}_{1}})\]                 \[+\,{{x}_{3}}({{y}_{1}}-{{y}_{2}})\}\] Given points are \[A(6,3),B(-3,5),C(4-,2)\] and \[p(x,y)\]                 \[\therefore \]  \[\frac{\Delta PBC}{\Delta ABC}\]                 \[=\frac{\frac{1}{2}}{\frac{1}{2}}\left[ \frac{x(5+2)-3(-2-y)+4(y-5)}{6(5+2)-3(-2-3)+4(3-5)} \right]\]                 \[=\left[ \frac{7x+7y-14}{42+15-8} \right]\]                 \[=\frac{7x+7y-14}{49}=\frac{x+y-2}{7}\]


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