The formula for the surface area of a triangular prism is SA = bh + (s1 + s2 + s3)H. In this formula, "b" is the triangle base, "h" is the triangle height, "s1," "s2" and "s3" are the three triangle sides, and "H" is the length of the prism.

A triangular prism can be thought of as two triangles and three quadrilaterals, so finding the total surface area involves finding the area of each of the five shapes and adding them together.

The area of a triangle is one half of the base multiplied by the height. The area of a quadrilateral is the base multiplied by the height.