10th Class Mathematics Areas Related to Circles Question Bank Area of Circle

  • question_answer
    In the given figure, PQRS is a square of diagonal \[7\sqrt{2}\,cm\]. With P as the centre, the arc QMS is drawn. What is the area of the shaded region \[(in\,\,c{{m}^{2}})\]?

    A)  \[\frac{49}{4}(\pi -2)\]

    B)  \[\frac{49}{4}(\pi -1)\]

    C)  \[\frac{49}{4}(\pi -3)\]

    D)  \[\frac{49}{2}(\pi -2)\]

    Correct Answer: A

    Solution :

    (a): (Refer to Q. 10: Area (QMS) \[=\frac{1}{2}\times \] standardized area as given is question 10). Area of shaded region = Area of the sector PQMS ? Area of triangle PQS \[QS=\sqrt{2}\] (side) \[=7\sqrt{2}\text{ }cm\] Side = 7cm Area of sector PQS\[=\frac{90{}^\circ }{360{}^\circ }\pi {{(7)}^{2}}=\frac{49\pi }{4}c{{m}^{2}}\] Area of triangle \[PQS=\frac{1}{2}\left( PQ \right)\left( PS \right)\]             \[=\frac{1}{2}{{(7)}^{2}}=\frac{49}{2}c{{m}^{2}}\] Required area \[=\left( \frac{49\pi }{4}-\frac{49}{2} \right)c{{m}^{2}}\]             \[=\frac{49}{4}(\pi -2)c{{m}^{2}}\]


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