2. Questions Bank
  3. 9th Class
  4. Mathematics
  5. Circles

9th Class Mathematics Circles Question Bank Circle

  • question_answer
    In the given figure below, A chord AB of a circle \[{{\mathbf{C}}_{\mathbf{1}}}\] of radius \[\left( \sqrt{\mathbf{2}}\mathbf{+1} \right)\]cm touches a circle\[{{\mathbf{C}}_{2}}\]which is concentric to\[{{\mathbf{C}}_{1}}\]. If the radius of \[{{\mathbf{C}}_{2}}\] is \[\left( \sqrt{\mathbf{2}}\mathbf{-1} \right)\] cm. The length of AB is:

    A)  \[3\sqrt[4]{3}\]cm         

    B)  \[6\sqrt{3}\]cm        

    C)  \[4\sqrt[4]{2}\]cm    

    D)  \[4\sqrt{3}\] cm

    Correct Answer: C

    Solution :

    (c): \[OC=\sqrt{2}-1\] \[OA=\sqrt{2}+1\] \[AC=\sqrt{{{\left( \sqrt{2}+1 \right)}^{2}}-{{\left( \sqrt{2}-1 \right)}^{2}}}\] \[=\sqrt{4\sqrt{2}}=2\sqrt[4]{2}\] \[\therefore \]\[AB=2AC=4.\sqrt[4]{2}cm.\]          


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