Question

If its perimeter of an equilateral triangle is $180cm$, what will be its area?

Answer 1

Side of equilateral triangle $=\frac{perimeter}{3}$

$=\frac{180}{3}$cm

$=60cm$

$\therefore$ Area of triangle $=\frac{\sqrt{3}{a}^2}{4}$

$\begin{array}{c}=\frac{\sqrt{3}\times 60\times 60}{4}\\ =\frac{3600\sqrt{3}}{4}\\ =900\sqrt{3}\end{array}$

Area of equilateral triangle is $900\sqrt{3}$.