The surface area composes of 4 triangles and 1 square.
The side length of the square is 7 m, so the area is 49 m^2 because the area of a square is the side length^2.
Each of the triangles has a base of length 7 m and a height of 8 m, so the area of each triangle is 7m*8m/2 = 28 m^2 because the area of a triangle is the base*height/2.
Since there are 4 triangles, the total surface area of the 4 triangles is 28 m^2 * 4 = 112 m^2.
Adding that to the area of the square, we get 49 m^2 + 112 m^2 = 161 m^2
