The altitude of an equilateral triangle having perimeter 18 m, is

The correct answer is Option (1) → \(3\sqrt{3}\) m

In an equilateral triangle the altitude meets the base at its midpoint, so it splits the triangle into two right triangles; Pythagoras’ theorem then gives the altitude.

• Side \(=18\div3=6\) m; half the base \(=3\) m

• \(h^2=6^2-3^2=36-9=27\)

• \(h=\sqrt{27}=\) \(3\sqrt{3}\) m