the surface area should be 544 (whatever the unit is)
Explanation:
You start by taking the rectangles on the side and finding their area.
1. (10×14)×2 ←Because there are two rectanglular sides.
2. find the area of the triangles on the side. 1/2bh = area of triangle.
(.5×8×6)×4 ← in order to find the area for all of the triangles.
3. lastly take the base of the prism and find the area then add the previously found values together.
(12×14)+(.5×8×6)×4+ (10×14)×2 = 544