Answer: 17 square inches.
Step-by-step explanation: Area of a triangle is 1/2 x b x h. We can just take the area of half of the whole triangle, and double it. In this case, half of the triangle has an area of 1/2 x 3.4 x 5 = 8.5. Doubling it is the same is doing 8.5 x 2, which equals 17.