10th Class Mathematics Introduction to Trigonometry Question Bank Case Based (MCQs) - Introduction to Trigonometry

  • question_answer
    Direction: Q. 11 to 15
    Three friends - Sanjeev, Amit and Digvijay are playing hide and seek in a park. Sanjeev and Amit hide in the shrubs and Digvijay have to find both of them. If the positions of three friends are at A, B and C respectively as shown in the figure and forms a right angled triangle such that \[\text{AB}=\text{9 m},\] \[\text{BC}=3\sqrt{3}\text{ m}\] and \[\angle B=90{}^\circ \].
    Based on the above information, give the answer of the following questions:
    The measure of \[\angle A\] is:

    A) \[30{}^\circ \]

    B) \[45{}^\circ \]

    C) \[60{}^\circ \]

    D) None of these

    Correct Answer: A

    Solution :

    We have, \[AB=9m,\] \[BC=3\sqrt{3}m\]
    In \[\Delta ABC,\]we have
    \[\tan A=\frac{BC}{AB}=\frac{3\sqrt{3}}{9}=\frac{1}{\sqrt{3}}\]
    \[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\tan A=\tan 30{}^\circ \,\,\,\,\,\,\Rightarrow \,\,\,\,\,\,\,\,\angle A=30{}^\circ \]  ….(1)
    So, option [a] is correct.


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