The formula for the area of a trapezoid is A = (b1 + b2)h/2, where b1 and b2 are the lengths of the two bases and h is the height of the trapezoid.
Plugging in the given values, we get A = (3 + 5)8/2 = 32 square yards.
Therefore, the area of the trapezoid is 32 square yards.