SSC Sample Paper SSC CGL - Sample Paper-10

  • question_answer
    If a wire is bent in to the shape of a square the area of the square is \[81\,c{{m}^{2}}.\] When the wire is bent into a semicircular shape, the area of the semicircle is \[\left( take\,\,\pi =\frac{22}{7} \right)\]

    A)  \[154\,c{{m}^{2}}\]   

    B)  \[77\,c{{m}^{2}}\]

    C)  \[44\,c{{m}^{2}}\]                 

    D)  \[22\,c{{m}^{2}}\]

    Correct Answer: A

    Solution :

    Let a be the side of square. \[{{a}^{2}}=81\] \[\Rightarrow \]   \[a=9\,cm\] \[\therefore \] Perimeter of square \[=4\times 9=36\,cm\] \[\therefore \] Length of wire \[=36\] \[\Rightarrow \]   \[\pi r+2r=36\]             \[r=\frac{36\times 7}{36}=7\,cm\] \[\therefore \]      Area of circle \[=\pi {{r}^{2}}\]             \[=\frac{22}{7}\times 7\times 7=154\,c{{m}^{2}}\]      

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