First, we need to find the area of the rectangle that the triangle RST is in, which would be 4*5=20. Second, we need to subtract the three triangles so the remaining area would be the area of the triangle that we need to solve for. The sum of the areas of the three triangles would be: 1/2*2*5 + 1/2*2*2 + 1/2*4*3 = 5 + 2 + 6 = 13.
