Answer:
8 x 6.9 x 1/2(basically just dividing by 2) 27.6 area of the base.
8 x 10 = 80, 80 divided by 2 = 40, 40 x 2(area of two triangles) = 80 area of two triangles on the side
8 x 10 = 80, 80 divided by 2 ( x 1/2) = 40 triangle area behind
Add all the given areas:
27.6 + 80 + 40 = 147.6 m^2 is your surface area.