RAJASTHAN ­ PET Rajasthan PET Solved Paper-2005

  • question_answer
    In\[\Delta \]ABC, if\[\angle A=30{}^\circ ,c=7\sqrt{3}\]and\[\angle C=90{}^\circ ,\] then the value of a is

    A)  \[\frac{7}{2}\]                

    B)  \[7\sqrt{3}\]

    C)  \[\frac{7}{2}\sqrt{3}\]              

    D)  \[7\sqrt{2}\]

    Correct Answer: C

    Solution :

     Given, in\[\Delta ABC,\angle A=30{}^\circ ,\angle C=90{}^\circ ,c=7\sqrt{3}\] By sine rule\[\frac{a}{\sin A}=\frac{c}{\sin C}\] \[\Rightarrow \] \[a\sin C=c\sin A\] \[\Rightarrow \] \[a\sin 90{}^\circ =7\sqrt{3}\sin 30{}^\circ \] \[\Rightarrow \] \[a=7\sqrt{3}.\frac{1}{2}\] \[\Rightarrow \] \[a=\frac{7}{2}\sqrt{3}\]


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