10th Class Mathematics Mensuration Question Bank Mensuration

  • question_answer
    The area of a right angled triangle is \[\text{2}0\text{ c}{{\text{m}}^{\text{2}}}\]and one of the sides containing the right triangle is 4 cm. Then the altitude on hypotenuse is

    A)  8 cm                     

    B)  10 cm

    C)  \[\frac{10}{\sqrt{41}}cm\]cm         

    D)         \[\frac{20}{\sqrt{29}}cm\]  

    Correct Answer: D

    Solution :

     Let length of the other perpendicular side be a cm and altitude on the hypotenuse is p cm.                 \[\therefore \]  \[\frac{1}{2}\times 4\times a=20\]                 or            \[a=10\,cms\] \[\therefore \] Hypotenuse \[=\sqrt{{{a}^{2}}+{{4}^{2}}}=\sqrt{{{10}^{2}}+{{4}^{2}}}=2\sqrt{29}\] Area of the triangle \[=\frac{1}{2}\times 2\sqrt{29}\times p=20\,sq.cm\] \[\therefore \]  \[p=\frac{20}{\sqrt{29}}\]


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