CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2007

  • question_answer
    If the angles of a triangle are in the ratio\[4:1:1,\]then the ratio of the longest side to the perimeter is

    A)  \[\sqrt{3}:2+\sqrt{3}\]                 

    B)  \[1:6\]

    C)  \[1:2+\sqrt{3}\]              

    D)         \[2:3\]

    E)  \[\sqrt{2}:2+\sqrt{3}\]

    Correct Answer: A

    Solution :

    Let the angles of a triangle are\[4x,\text{ }x\]and\[x\] respectively. \[\therefore \]  \[4x+x+x=180{}^\circ \] \[\Rightarrow \]               \[x=30{}^\circ \] We know that \[a:b:c\] \[=sin\,A:sin\,B:sin\,C\] \[=sin\text{ }120{}^\circ :\text{ }sin\text{ }30{}^\circ :\text{ }sin\text{ }30{}^\circ \]                 \[=\frac{\sqrt{3}}{2}:\frac{1}{2}:\frac{1}{2}=\sqrt{3}:1:1\] Let the sides of a triangle are\[\sqrt{3}y,y\]and\[y\]. \[\therefore \]Perimeter of a triangle\[=(\sqrt{3}+1+1)y\] Hence, required ratio \[=\frac{\sqrt{3}y}{(2+\sqrt{3})y}\]                                 \[=(\sqrt{3}):(2+\sqrt{3})\]


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