Answer
the length of each side is $a=2.9~ft$
Work Step by Step
Since the area is an equilateral triangle, then all three sides are the same length. The formula for the area of an equilateral triangle is $A=\frac{\sqrt 3a^{2}}{4}$, where the base is one of the sides (let's express it with the variable $a$). This formula can be obtained using trigonometric functions with the angles inside of the triangle after bisecting the triangle with a perpendicular height.
Solving for $a$ in the formula, we get:
$a=\sqrt {\frac{4A}{\sqrt 3}}=\sqrt {\frac{4(3.6ft^{2})}{\sqrt 3}}=2.88ft\approx 2.9~ft$
