If the area of an equilateral triangle is 40\(\sqrt {3}\) sq. cm.  Find side of the triangle.

6\(\sqrt {10}\) cm 3\(\sqrt {10}\) cm 4\(\sqrt {10}\) cm 5\(\sqrt {10}\) cm

4\(\sqrt {10}\) cm

Area of an equilateral triangle = \(\frac{\sqrt {3}}{4} a^2\) ⇒ 40\(\sqrt {3}\) =  \(\frac{\sqrt {3}}{4} a^2\) ⇒ 40 × 4 = a2 ⇒ a = 4\(\sqrt {10}\) cm