Multiple Choice Question (MCQ)
The three sides of a triangle are 5m, 6m and 7m respectively. Which one below is the area of the triangle?
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×
15 m^2
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✓
6 \sqrt{6} m^2
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×
21 m^2
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×
9 m^2
Answer
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According to Helen's formula, the area of a triangle is
A = \sqrt{p(p-a)(p-b)(p-c)} ,
in which a, b, c is the length of three sides of the triangle,
p = \dfrac{1}{2} (a+b+c)
\therefore A = \sqrt{9×4×3×2 } = 6 \sqrt{6}