Step-by-step explanation:
In the mensuration of a triangular prism we can find the total surface area by solving for the areas of  individual shape.
The triangular prism consist of
1. three rectangular surfaces
2. two triangular surfaces.
Hence the total surface area is the sum of the areas of the rectangular surface
= [tex](l* w) +( l*w)+(l*w)\\[/tex]
and the sum of all areas of triangular surfaces
= [tex](\frac{1}{2}bh) + (\frac{1}{2}bh)[/tex]
In summary just find the area of each shape and add them together.
