Triangular pyramid is a pyramid which has a triangular base. A pyramid with polygonal base and triangular faces are equal to the number of sides in the base. Each and every triangular face will have different size and shape. It has three faces, six edges and four vertices. This page provides the surface area of a triangular pyramid formula to calculate surface area based on the apothem length, side length and slant height of the triangular pyramid.
The above surface area of a triangular pyramid formula is defined as ((ab) + (3bl)) / 2. This formula would be helpful for you in calculating SA. You can also use the online calculator given above for finding the surface area.