A triangular prism is composed of 2 triangles and 3 rectangles.
1 triangle has 2 right triangle, for a total of 4 right triangles.
Area of a right triangle = ab/2 = (3.5m * 2m)/2 = 7/2 = 3.5m²
3.5m² x 4 right triangles = 14 m² total area of the triangle bases.
Rectangle: length = 11 m ; width = 4m
Area of a rectangle = L * W = 11m * 4m = 44m²
44m² x 3 rectangles = 132 m² total area of the rectangle faces
Surface area = 132 m² + 14 m² = 146 m²