PDF chapter test TRY NOW
Area of an equilateral triangle using Heron's formula:
\(AB\) \(=\) \(BC\) \(=\) \(CA\) \(=\) \(a\)
That is, \(a\) \(=\) \(b\) \(=\) \(c\)
\(s\) \(=\) \(=\)
Area of a triangle \(=\)
\(=\)
\(=\)
\(=\)
\(=\)
\(=\)
\(=\)
Therefore, the area of an equilateral triangle \(=\) sq. units.
Example:
Calculate the area of an equilateral triangle of side \(4 \ cm\).
\(a\) \(=\) \(b\) \(=\) \(c\) \(=\) \(4 \ cm\)
Area of an equilateral triangle \(=\)
\(=\)
\(=\)
\(=\) \(\sqrt{3} \times 4\)
\(=\) \(1.73 \times 4\) [Since \(\sqrt{3} = 1.73\)]
\(=\) \(6.92\)
Therefore, the area of an equilateral triangle \(=\) \(6.92 \ cm^2\).