To find the surface area, we need to find the area of each piece.
Bottom:
6 * 15 = 60 + 30 = 90
Triangles (both) :
6 * 10 = 60
Top (both) :
Pythagorean ----> sqrt(109) * 15 * 2 = 30sqrt(109)
Now, add it all together:
90 + 60 + 30sqrt(109) = 150 + 30sqrt(109)
:)
