The perimeter of an equilateral triangle is 90 cm. Find

1. 225√3 sq cm
2. 250√3 sq cm
3. 135√3 sq cm
4. 151√3 sq cm
5. None of the above

Given that, perimeter = 90 cm
⇒ 3a = 90 cm [a = side]
∴ a = 90/3 = 30 cm
∴ Area = √3a² / 4 = √3/4 x (30)²
= 900 x √3/4 = 225√3 sq cm