The perimeter of an equilateral triangle is 12 ft find the are of the triangle

For a side of length s, the area of an equilateral triangle is

... A = (√3) / 4·s²

The perimeter is the sum of the three equal side lengths, so we have

... 12 ft = 3s

... 4 ft = s

Then the area is

... A = (√3) / 4· (4 ft) ²

... A = 4√3 ft² ≈ 6.928 ft²