Question

In an equilateral triangle of sides $3\sqrt{3}$cm.Find the length of its altitude.

Answer 1

R.E.F image

$x=\sqrt{(3\sqrt{3}{)}^2-(\frac{3\sqrt{3}}{2}{)}^2}$

$=3\sqrt{3}\sqrt{1-\frac{1}{4}}$

$=3\sqrt{3}\sqrt{\frac{3}{4}}$

$=\frac{3\sqrt{3}.\sqrt{3}.}{2}=\frac{9}{2}$

Length of the altitude = $\frac{9}{2}$ cm .