The area of a triangle can be calculated by multiplying its base length by its height and then dividing the result by 2.
Using this formula, the area of the triangle with a base length of 3 1/2 inches and a height of 3 inches can be calculated as:
Area = (base x height) / 2
Area = (3.5 inches x 3 inches) / 2
Area = 10.5 square inches / 2
Area = 5.25 square inches
Therefore, the area of the triangle is 5.25 square inches.