It is known that the surface area of a straight triangular prism whose base is an equilateral triangle is a square with side length of 3 Only know the side length of the triangle, then how to calculate the area of the triangle?

It is known that the surface area of a straight triangular prism whose base is an equilateral triangle is a square with side length of 3 Only know the side length of the triangle, then how to calculate the area of the triangle?

The surface area is 3 & # 178; + (√ 3 / 4) × 1 & # 178; × 2 = 9 + # 3 / 2 (area unit)