Correct Answer - Option 3 : 108√3 cm
2
Given:
Height of an equilateral triangle = 18 cm
Concept:
Height of equilateral triangle = (√3/2) × a
Area of equilateral triangle = (√3/4) × a2
Calculation:
According to the problem,
⇒ (√3/2) × a = 18
⇒ a = 12√3
Area of the equilateral triangle = (√3/4) × a2
⇒ (√3/4) × (12√3) 2 = 108√3 cm2
∴ Area of the equilateral triangle is 108√3 cm2