10th Class Mathematics Areas Related to Circles Question Bank MCQs - Areas Related to Circles

  • question_answer
    In the figure, PQRS is a square, O is centre of the circle. If \[RS=10\sqrt{2}\,cm,\] then area of shaded region is:      

    A) \[(90\pi -90)c{{m}^{2}}\]

    B) \[(80\pi -80)c{{m}^{2}}\]

    C) \[(50\pi -100)c{{m}^{2}}\]

    D) \[(100\pi -100)c{{m}^{2}}\]

    Correct Answer: C

    Solution :

    [c] Diagonal of square
    \[=\sqrt{2}\,\,(side)=\sqrt{2}\times (10\sqrt{2})\]
    \[=20cm\]
    \[\therefore \]   Diameter of circle \[=20cm\]
    \[\therefore \]  Radius of circle \[(r)=\frac{20}{2}=10cm\]
    Area of circle \[=\pi {{r}^{2}}=\pi \times {{(10)}^{2}}=100\pi c{{m}^{2}}\]
    Area of square \[={{(side)}^{2}}={{(10\sqrt{2})}^{2}}=200c{{m}^{2}}\]
    Area of circle not included in the square
    \[=(100\pi -200)c{{m}^{2}}\]
    \[\therefore \]  Area of shaded portion \[=\frac{1}{2}(100\pi -200)\]
    \[=(50\pi -100)c{{m}^{2}}\]


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