9th Class Mathematics Circles Question Bank Circles

  • question_answer
    A line AB intersects a circle with centre O and radius 2 cm at a point B. C is any other point on the circle in line with O and A, Find the measure of AC.

    A)  4 cm                          

    B) \[2+\sqrt{2}\,cm\]  

    C)  \[4\sqrt{2}\,cm\]        

    D)   \[2+2\sqrt{2}\,cm\]

    Correct Answer: D

    Solution :

    Join OB, Then  \[\angle OBA={{90}^{o}}\] \[A{{B}^{2}}+O{{B}^{2}}=A{{O}^{2}}.\] \[\therefore \]\[OB=AB=2\,cm\] Hence \[A{{O}^{2}}={{2}^{2}}+{{2}^{2}}\]or \[AO=2\sqrt{2}\,cm\] \[\therefore \]\[AC=AO+OC=\left( 2\sqrt{2}+2 \right)cm\]


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