The equation for the surface area of the triangular pyramid net shown in the image is:
SA = (1/2 * base * height) + (1/2 * perimeter * slant height)
SA = (1/2 * 17 * 14.72) + (1/2 * (11 * 3) * 10.99)
SA = (8.5 * 14.72) + (5.5 * 3 * 10.99)
SA = 125.2 + 181
SA = 306.2 square millimeters.