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

  • question_answer
    If the perimeter of a circle is equal to that of a square, then the ratio of their areas is

    A) 22:7

    B) 14:11

    C) 7:22

    D) 11:14

    Correct Answer: B

    Solution :

    Let radius of circle be r and side of a square be a. According to the given condition, Perimeter of a circle = Perimeter of a square \[\therefore \,\,\,2\pi r=4a\Rightarrow a=\frac{\pi r}{2}\]  .....(i) Now,\[\frac{Area\text{ }of\text{ }circle}{Area\,of\,square}=\frac{\pi {{r}^{2}}}{{{\left( a \right)}^{2}}}=\frac{\pi {{r}^{2}}}{{{\left( \frac{\pi r}{2} \right)}^{2}}}\] [from Eq. (i)] \[=\frac{\pi {{r}^{2}}}{{{\pi }^{2}}{{r}^{2}}/4}=\frac{4}{\pi }=\frac{4}{22/7}=\frac{28}{22}=\frac{14}{11}\]


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