find area of triangle whose sides are 11 cm , 8 cm , 13cm . fIND THE ALTITUDE using longest side as base .

Take  a=11 cm, b=8 cm, c=13 cmThe semi perimeter is given by,    s=a+b+c2      =11 cm+8 cm+13 cm2      =322cm      =16 cmThe area of the traingle is given by Heron's formula,             Area=s s-a s-b s-c                              =16 16-11 16-8 16-13                              =16 5 8 3                              =2×2×2×2 5 2×2×2 3                              =2×2×22×3×5                            =830 cm2Note that the area of ABC is also given by the formula,     area =12×base×altitude     area =12×c×altitude  Substitute the values to get,            830 =12×13×altitude    altitude= 2× 83013                = 163013                 =6.74 cm   approx

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