SSC Sample Paper Mock Test-9 SSC CGL Tear-II Paper-1

  • question_answer
    If   ABCD    is    a   rhombus,    then \[A{{B}^{2}}+B{{C}^{2}}+C{{D}^{2}}+A{{D}^{2}}\]is equal to

    A)  \[A{{D}^{2}}+B{{C}^{2}}\]

    B)         \[A{{O}^{2}}+O{{C}^{2}}\]

    C)  \[A{{C}^{2}}+B{{D}^{2}}\]

    D)  \[4\,\,(A{{O}^{2}}+O{{B}^{2}})\]

    Correct Answer: D

    Solution :

    As diagonals of a rhombus bisect each other at right angles. \[\Rightarrow \]AO = OC and BO = OD Applying Pythagoras theorem to \[\Delta AOB,\]\[\Delta AOD,\]\[\Delta DOC,\]\[\Delta BOC\]and on adding \[A{{B}^{2}}+B{{C}^{2}}+C{{D}^{2}}+A{{D}^{2}}\] \[=2\,\,[A{{O}^{2}}+O{{C}^{2}}+B{{O}^{2}}+D{{O}^{2}}]=2\,\,[2A{{O}^{2}}+2B{{O}^{2}}]\]


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