The area of the triangle with height 12 inches and the base of 5 inches is 30 square inches. The area (A) of a triangle with height, h, and base, b, is: A = h b / 2. We know that h = 12 in and that b = 5 in. Therefore, the area of this triangle will be: A = 12 in 5 in / 2 = 60 in^2 / 2 = 30 in^2. The area of the triangle is 30 square inches.