The answer depends on what the formula is for: the surface area, the volume, the number of edges, vertices, sides. Since you have not bothered to share that crucial bit of information, I cannot provide a more useful answer.
What is the formula for a triangular prism
Find the area of a triangular section, 1/2bh, and then multiply by the length of the prism.
It depends on the size of the triangular prism, but depending on the side of the prism you use the triangle area formula to find it or the rectangle area formula to find it.
Assume that a = apothem length of the triangular prism, b = base length of the triangular prism, and h = height of the triangular prism. The formulas to find the surface area is SA = ab + 3bh.
Triangular prism = 2 triangles + 3 rectangles.
There is no way to find perimeter from a 3D figure. However, you can find the perimeter of a side of a triangular prism by using perimeter formulas for a parallelogram or triangle.
Length of prism * perimeter of triangular face.
triangular prism- formula: Abh(area of the base * height)
Mass = Density x Volume
You find the volume of a triangular prism by using this formula: Volume = 1/2 base of the triangle x height of the triangle x height of the prism.
The answer depends on the formula for what characteristic of the prism.
It depends on triangular what: pyramid, dipyramid, prism, ...