JEE Main & Advanced Mathematics Trigonometric Equations Question Bank Relation between sides and angles, Solutions of triangles

  • question_answer
    The sides of a triangle are 4, 5 and 6cm. The area of the triangle is equal to [UPSEAT 2004]

    A) \[\frac{15}{4}c{{m}^{2}}\]

    B) \[\frac{15}{4}\sqrt{7}c{{m}^{2}}\]

    C) \[\frac{4}{15}\sqrt{7}c{{m}^{2}}\]

    D) None of these

    Correct Answer: B

    Solution :

    We have, \[a=4cm\], \[b=5cm\],\[c=6cm\] Semi-perimeter (s) = \[\frac{a+b+c}{2}\]= \[\frac{4+5+6}{2}=\frac{15}{2}\] cm      Area of triangle = \[\sqrt{s\,(s-a)\,(s-b)\,(s-c)}\] = \[\sqrt{\frac{15}{2}\,\left( \frac{15}{2}-4 \right)\,\left( \frac{15}{2}-5 \right)\,\left( \frac{15}{2}-6 \right)}\,\]= \[\frac{15}{4}\sqrt{7}c{{m}^{2}}\].


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