How do i find the surface area of this triangular prism?

The lateral surface area is the product of the triangle perimeter and the length of the prism:
.. lateral area = (6 m +10 m +8 m)*(9 m) = 216 m^2

The end area is twice that of the end triangles, so is
.. end area = (6 m)*(8 m) = 48 m^2

The total area is the sum of these.
.. total area = lateral area + end area
.. total area = 216 m^2 +48 m^2 = 264 m^2

The 8th term is 512