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

  • question_answer
    In the given figure, the ratio of the areas of two sectors \[{{S}_{1}}\] and \[{{S}_{2}}\] is:

    A) \[5:2\]   

    B) \[3:5\]

    C) \[5:3\]

    D) \[4:5\]

    Correct Answer: D

    Solution :

    [d] Let r be the radius of the circle.
    \[\therefore \]Area of the sector is given by \[\frac{\theta }{360{}^\circ }\times \pi {{r}^{2}}.\]    
    Area of sector \[{{S}_{1}}=\frac{120{}^\circ }{360{}^\circ }(\pi {{r}^{2}})=\frac{\pi {{r}^{2}}}{3}\]
    Are of sector \[{{S}_{2}}=\frac{150{}^\circ }{360{}^\circ }(\pi {{r}^{2}})=\frac{5\pi {{r}^{2}}}{12}\]
    \[\therefore \] Required ratio \[=\frac{\pi {{r}^{2}}}{3}:\frac{5\pi {{r}^{2}}}{12}=4:5\]


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