7th Class Mathematics Mensuration Question Bank Mensuration

  • question_answer
    The length of a rectangle is \[\frac{6}{5}\]th of its breadth. If its perimeter is 132m, its area will be............

    A)  \[1,080\,{{m}^{2}}\]         

    B)  \[640\,{{m}^{2}}\]

    C)  \[1,620\,{{m}^{2}}\]          

    D)  \[2,160\,{{m}^{2}}\]

    Correct Answer: A

    Solution :

        Let breadth\[=b\,m\] Then, length\[=\frac{6}{5}b\,m\] \[\because \]     Perimeter\[=132\] \[\therefore \]    \[2(b+\frac{6}{5}b)=132\Rightarrow b=30\,m\] Hence, length\[=\frac{6}{5}\times 30=36m\] And area\[=\]length\[\times \]breadth  \[=36\times 30=1080\,{{m}^{2}}.\]         


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