Question

The area of an equilateral triangle is $400\sqrt{3}{m}^2$. Its perimeter is:

• A. $120m$
• B. $150m$
• C. $90m$
• D. $135m$

Answer 1

The correct option is A $120m$

Let side of triangle$=am$
$\therefore$ area of equilateral$\Delta =\frac{\sqrt{3}}{4}{a}^2\frac{\sqrt{3}}{4}{a}^2=400\sqrt{3}{a}^2=1600a=\sqrt{1600}=40m$
$\therefore$ perimeter of equilateral $\Delta =3a=3\times 40=120m$