Altitude = Height = 6 cm
Let length of side be 'a'
So , √3/2 a = 6
So a = 12/√3
So a = 4√3 cm
This 'a' is the length of the side
Now, area = (√3/4) × a²
So, Area = (√3/4) × (4√3)²
So, Area = (√3/4) × (16×3)
So, Area = ✓3 × 4 × 3
So, Area = 12√3
So, Area = 12×1.732
So, Area = 20.784 cm²