A = 1/2 bh
where: A = area
b = length of the base
h = height of the triangle
Using the given,
33.6 = 1/2 (b)(4) substitute the given values
33.6 = 2b simplify the right side; 1/2(4) = 2
16.8 = b divide both side by 2
Therefore, the length of the base is 16.8 inches.