Suppose the triangle is labeled ABC. That is, angle A, angle B and angle C. The opposite sides for the respective angles are labeled a, b and c.
let a = 300, b = 250, c = 420
The smallest angle should correspond to the shortest side. So 36 degrees is angle B. Thus, we have sides a and c, with an included angle B. The area of the triangle is calculated as half of the products of the two sides with sine of the included angle.
Area = (a × c × sinB) / 2
Area = (300 ft × 420 ft × sin36) / 2
Area is 37,030 ft2.
Thus, the answer is letter C.