Correct Answer - Option 2 : 12 cm

**Given**

Area of equilateral triangle = 36√3 cm^{2}

**Formula used**

Area of a triangle = (√3/4) × (side)^{2}

**Calculation**

36√3 = (√3/4) × (side)^{2}

⇒ 144 = (side)^{2}

⇒ √144 = side

⇒ 12 cm = side

**∴ Side of an equilateral triangle is 12 cm.**