Answer:
The product of the perimeter of the triangle and the height of the prism
Explanation:
we know that
The surface area of a triangular prism is equal to

where
B is the area of the triangular base
P is the perimeter of the triangular face
h is the height of the prism
so
The meaning of Ph is the product of the perimeter of the triangle and the height of the prism (lateral area)