To find the surface area we can find the area of each face and sum them
the we find the area of each face, whe have 3 triangles around and a triangle on base
Triangles around are the same triangle then I calculate one area
area
area of this face is 21.6sqaure yd
Base triangle
area
area of this face is 15.6 sqaure yd
Surface
we sum the area of each face, 3 Frist triangles and the triangle of the base
Total surface area is 80.4 square yards