What we must do is observe that the triangles have the same measurements.
We have then that the surface area is:
A = (4) * (1/2) * (b) * (h)
Where,
b: base of the triangle
h: height of the triangle
Substituting values:
A = (4) * (1/2) * (8) * (6.9)
A = 110.4 cm ^ 2
Answer:
The surface area of the triangular pyramid is:
A = 110.4 cm ^ 2