Question

Find the length of the altitude of an equilateral triangle with side $6$cm.

Answer 1

Let the length of the altitude of an equilateral triangle be $xcm$

Given the sides of the equilateral triangle is $6cm$

From the figure,

$x=\sqrt{6^2-3^2}$

$=\sqrt{36-9}$

$=\sqrt{27}$

$=3\sqrt{3}$

$\therefore x=3\sqrt{3}cm\approx 5.1961cm$

Thus, the altitude of the triangle is $3\sqrt{3}cm$ or $5.1961cm$