10th Class Mathematics Areas Related to Circles Question Bank Case Based (MCQs) - Areas Related to Circles

  • question_answer
    Find the area swept by the hour hand in 1 hour.

    A) \[\text{7}.\text{68 c}{{\text{m}}^{\text{2}}}\]

    B) \[\text{8}\text{.2 c}{{\text{m}}^{\text{2}}}\]

    C) \[\text{8}\text{.86 c}{{\text{m}}^{\text{2}}}\]

    D) \[\text{9}.\text{428 c}{{\text{m}}^{\text{2}}}\]

    Correct Answer: D

    Solution :

    [d] Angle made by hour hand in 1 hour
    \[=\frac{360{}^\circ }{12}=30{}^\circ \]
    Also,     \[r=6cm\]
    \[\therefore \] Area swept made by hour hand in 1hour
    =Area of sector having central angle \[30{}^\circ \]
    \[=\pi {{r}^{2}}\times \left( \frac{30{}^\circ }{360{}^\circ } \right)=\frac{22}{7}\times 6\times 6\times \frac{1}{12}=\frac{66}{7}\]\[=9.428c{{m}^{2}}\]

You need to login to perform this action.
You will be redirected in 3 sec spinner